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1.
Water Sci Technol ; 83(6): 1315-1326, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33767038

RESUMO

The aim of this study was to provide technical means and data support for enhancing the filtration pretreatment capacity of a recirculating aquaculture system. A continuous flow electrocoagulation (EC)-filtration system was designed and its application in the pretreatment of marine aquaculture wastewater was studied. The influences of anode combination modes, hydraulic retention times (HRTs) of the EC reactor and filter pore sizes on the water treatment capacity were investigated. Results showed that EC could significantly enhance the treatment efficiency of the filtration equipment used in subsequent steps. Al-Fe electrodes used as anode led to better processing capacity of this system, and the optimum anode was 3Al + Fe. With the increase of HRT and decrease of filter pore size, the enhanced effect of the EC process on the filter was more obvious. When the current density was 19.22 A/m2, the anode was 3Al + Fe, the HRT was 4.5 min and the filter pore size was 45 µm, the removal efficiency of the system for Vibrio, chemical oxygen demand, total ammonia nitrogen, nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N) and total nitrogen was 69.55 ± 0.93%, 48.99 ± 1.42%, 57.06 ± 1.28%, 34.09 ± 2.27%, 18.47 ± 1.88% and 55.26 ± 1.42%, respectively, and the energy consumption was (26.25 ± 4.95) × 10-3kWh/m3.


Assuntos
Águas Residuárias , Purificação da Água , Aquicultura , Eletrocoagulação , Eletrodos , Filtração , Eliminação de Resíduos Líquidos
2.
Zhonghua Er Ke Za Zhi ; 59(3): 201-205, 2021 Mar 02.
Artigo em Chinês | MEDLINE | ID: mdl-33657694

RESUMO

Objective: To study the clinical characteristics and risk factors of post polypectomy electrocoagulation syndrome (PPECS) in children. Methods: Clinical data of 23 children with PPECS in Children's Hospital Affiliated to Zhengzhou University from January 2015 to December 2019 were retrospectively analyzed. Additionally, 115 children without PPECS who had polypectomy performed by the same endoscopist at the same time were collected into the control group. The morbidity, clinical characteristics and therapeutic protocol were analyzed, and the risk factors of PPECS were analyzed by Logistic regression. Results: Among the total 2 083 children who had endoscopic polypectomy with electrocautery, 23 children (1.1%) developed PPECS. All had abdominal pain and fever. The average age of the children with PPECS was (3.5±1.5) years, including 19 cases (82.6%) younger than 3 years. There were 18 cases with polyps larger than 25 mm (78.3%). The endoscopic operation time ((56±15) vs. (24±8) min, t=18.086, P<0.01), the rate of piecemeal resection (78.3% (18/23) vs. 17.4% (20/115), χ2=17.358, P<0.01), the lesion size ((38.4±3.7) vs. (15.8±4.3) mm, t=15.127, P<0.01), the proportion of polyps located in the right hemicolon (47.8% (11/23) vs. 23.5% (27/115), χ2=7.035, P<0.05), and the proportion of broad-based polyps (78.3% (18/23) vs. 25.2% (29/115), χ2 = 29.259, P<0.01) in the PPECS group were all significantly higher than those in the non-PPECS group. Similarly, the leukocyte counts ((17.4±4.5)×109/L vs. (8.5±1.2)×109/L, t=6.085, P<0.05) and C-reactive protein ((25.8±3.6) vs. (1.1±0.6) mg/L, t=5.531, P<0.05) in the PPECS group were higher than those in the non-PPECS group. The results of multivariate Logistic regression analysis indicated that lesion size ≥25 mm (OR=7.554, 95%CI 3.135-20.158, P=0.001), broad-based polyps (OR=5.676, 95%CI 1.153-9.596, P=0.002) and lesion located in the right hemicolon (OR=5.845, 95%CI 1.737-9.297, P=0.008) were independent risk factors of PPECS. Conclusions: The clinical features of PPECS in children are fever, abdominal pain and leukocytosis after the procedure. The lesion size ≥ 25 mm, broad-based polyps and lesion located in the right hemicolon are the independent risk factors of pediatric PPECS.


Assuntos
Dor Abdominal , Endoscopia , Criança , Pré-Escolar , Colonoscopia , Eletrocoagulação/efeitos adversos , Humanos , Estudos Retrospectivos , Fatores de Risco
3.
J Environ Manage ; 285: 112068, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33581453

RESUMO

Electrocoagulation (EC) with an aluminum electrode arrangement as anode-cathode was applied to denitrify groundwater and electrooxidation (EO) was examined as a post-treatment step to remove the produced by-products. Initially, EC experiments were performed under batch operating mode using artificially-polluted tap water to investigate the effects of initial pH (5.5, 7.5, 8.5), initial NO3--N concentration (25, 35, 45, 55 mg L-1) and applied current density (10, 20 mA cm-2) on process efficiency. The effect of initial solution pH on ammonium cation concentration was also investigated as their generation (as a by-product) is the main drawback preventing wide-scale application of these treatment processes. Experimental results revealed high nitrate removal percentages (up to 96.3%) for initial pH 7.5 and all initial concentrations and current densities, while the final ammonium concentrations ranged between 5.3 and 9.2 mg NH4+-N L-1 (for initial NO3--N of 25 mg L-1). Therefore, EO was examined to oxidize the ammonium cations to nitrogen gas on iridium oxide coated titanium electrodes (IrO2/Ti) anode surface. The effects of cathode material (aluminum, stainless steel), total current density and anode surface area (3.3-30 mA cm-2 and 12-36 cm2, respectively) were investigated, and lead to NH4+-N percentage removals of between 25% (10 mA cm-2, 12 cm2) and 100% (30 mA cm-2, 24 cm2) for an initial NH4+-N concentration of 10 mg L-1. The optimum EC (20 mA cm-2, natural initial pH 7.5-7.8) and EO parameters (30 mA cm-2, 24 cm2 surface area anode, Al cathode) were combined into a hybrid system to treat two real nitrate-polluted groundwaters with initial NO3--N concentrations of 25 and 75 mg L-1. Results revealed that the proposed hybrid treatment system can be used to efficiently remove nitrate from groundwaters.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Desnitrificação , Eletrocoagulação , Eletrodos , Nitratos
4.
Environ Sci Technol ; 55(4): 2674-2683, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33533250

RESUMO

It is imperative to understand the behavior of enveloped viruses during water treatment to better protect public health, especially in the light of evidence of detection of coronaviruses in wastewater. We report bench-scale experiments evaluating the extent and mechanisms of removal and/or inactivation of a coronavirus surrogate (ϕ6 bacteriophage) in water by conventional FeCl3 coagulation and Fe(0) electrocoagulation. Both coagulation methods achieved ∼5-log removal/inactivation of ϕ6 in 20 min. Enhanced removal was attributed to the high hydrophobicity of ϕ6 imparted by its characteristic phospholipid envelope. ϕ6 adhesion to freshly precipitated iron (hydr)oxide also led to envelope damage causing inactivation in both coagulation techniques. Fourier transform infrared spectroscopy revealed oxidative damages to ϕ6 lipids only for electrocoagulation consistent with electro-Fenton reactions. Monitoring ϕ6 dsRNA by a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) method quantified significantly lower viral removal/inactivation in water compared with the plaque assay demonstrating that relying solely on RT-qPCR assays may overstate human health risks arising from viruses. Transmission electron microscopy and computationally generated electron density maps of ϕ6 showed severe morphological damages to virus' envelope and loss of capsid volume accompanying coagulation. Both conventional and electro- coagulation appear to be highly effective in controlling enveloped viruses during surface water treatment.


Assuntos
Ferro , Purificação da Água , Eletrocoagulação , Humanos , Inativação de Vírus , Águas Residuárias
5.
Chemosphere ; 272: 129614, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33482514

RESUMO

Anodic passivation is a key problem to reduce the efficiency of electrocoagulation (EC) process. Super-gravity technology was introduced into EC process to enhance the treatment of heavy metal wastewater using pure aluminum electrode. The results showed that the removal ratio of Cu increased, and the cell voltage decreased with the increase of gravity coefficient, suggesting a promoting effect of super-gravity field on electrocoagulation process. Electrochemical behavior of aluminium anode in super-gravity field was analyzed by potentiodynamic polarization, cyclic voltammetry and electrochemical impedance spectroscopy. It was found that anodic polarization behavior of aluminium showed a typical characteristic of dissolution in super-gravity, rather than passivation in normal gravity. The type of anode dissolution changed from pitting corrosion to uniform corrosion in super-gravity field. The outer oxidized film of anode was thinning, and more Al3+ ions were released by anode dissolution, which was attributed to the super-gravity enhancement of the mass transfer process of Cl- ions. In addition, X-ray diffraction and Fourier transform infrared spectroscopy indicated that the flocs generated in super-gravity field had amorphous and looser Al-O framework structure. As a result, the efficiency of EC process was improved by super-gravity.


Assuntos
Alumínio , Águas Residuárias , Cobre , Eletrocoagulação , Eletrodos , Eliminação de Resíduos Líquidos
6.
Bioresour Technol ; 323: 124606, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33385625

RESUMO

Centrifugation is the most commonly used method for harvesting autotrophically produced microalgae, but it is expensive due to high energy demands. With the aim of reducing these costs, we tested electrocoagulation with iron electrodes for harvesting Chlorella vulgaris. During extensive lab-scale experiments, the following factors were studied to achieve a high harvesting efficiency and a low iron content in the harvested biomass: electric charge, initial biomass concentration, pH, temperature, agitation intensity, residual salt content and electrolysis time. A harvesting efficiency greater than 95% was achieved over a broad range of conditions and the residual iron content in the biomass complied with legislative requirements for food. Using electrocoagulation as the pre-concentration step prior to centrifugation, total energy costs were reduced to 0.136 kWh/kg of dry biomass, which is less than 14% of that for centrifugation alone. Our data show that electrocoagulation is a suitable and cost-effective method for harvesting microalgae.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Eletrocoagulação , Eletrólise , Floculação
7.
Ecotoxicol Environ Saf ; 209: 111855, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33385676

RESUMO

OBJECTIVES: The composition and concentration distribution of volatile organic compounds (VOCs) in surgical smoke had seldomly been reported. This study aimed to investigate the profile of VOCs and their concentration in surgical smoke from breast surgery during electrocautery in different tissues, electrosurgical units, and electrocautery powers. METHODS: Thirty-eight surgical smoke samples from 23 patients performed breast surgery were collected using evacuated stainless steel canisters. The concentrations of 87 VOCs in surgical smoke samples were analyzed by gas chromatography-mass spectrometry. The human tissues, electrosurgical units, and electrocautery power were recorded. RESULTS: The median level of total VOCs concentrations in surgical smoke samples from mammary glands (total VOCs: 9953.5 ppb; benzene: 222.7 ppb; 1,3-butadiene: 856.2 ppb; vinyl chloride: 3.1 ppb) using conventional electrosurgical knives were significantly higher than that from other tissues (total VOCs: 365.7-4266.8 ppb, P < 0.05; benzene: 26.4-112 ppb, P < 0.05; 1,3-butadiene: 15.6-384 ppb, P < 0.05; vinyl chloride: 0.6-1.8 ppb, P < 0.05) using different electrosurgical units. A high methanol concentration was found in surgical smoke generated during breast surgery (641.4-4452.5 ppb) using different electrosurgical units. An electrocautery power of ≥ 27.5 watts used for skin tissues produced a higher VOCs concentration (2905.8 ppb). CONCLUSIONS: The surgical smoke samples collected from mammary glands using conventional electrosurgical knives had high VOCs concentrations. The carcinogens (including benzene, 1,3-butadiene, and vinyl chloride) and methanol were found in the surgical smoke samples from different electrosurgical units. The type of electrosurgical unit and electrocautery power used affected VOCs concentrations in surgical smoke.


Assuntos
Poluentes Atmosféricos/análise , Salas Cirúrgicas , Compostos Orgânicos Voláteis/análise , Benzeno/análise , Neoplasias da Mama , Butadienos , Carcinógenos/análise , Eletrocoagulação , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Fumaça/análise
8.
Cochrane Database Syst Rev ; 1: CD009497, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33507555

RESUMO

BACKGROUND: Primary liver tumours and liver metastases from colorectal carcinoma are two of the most common malignant tumours to affect the liver. The liver is second only to the lymph nodes as the most common site for metastatic disease. More than half of the people with metastatic liver disease will die from metastatic complications. Electrocoagulation by diathermy is a method used to destroy tumour tissue, using a high-frequency electric current generating high temperatures, applied locally with an electrode (needle, blade, or ball). The objective of this method is to destroy the tumour completely, if possible, in a single session. With the time, electrocoagulation by diathermy has been replaced by other techniques, but the evidence is unclear. OBJECTIVES: To assess the beneficial and harmful effects of electrocoagulation by diathermy, administered alone or with another intervention, versus no intervention, other ablation methods, or systemic treatments in people with liver metastases. SEARCH METHODS: We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, Science Citation Index Expanded, Conference Proceedings Citation Index - Science, CINAHL, ClinicalTrials.gov, ICTRP, and FDA to October 2020. SELECTION CRITERIA: We considered all randomised trials that assessed beneficial and harmful effects of electrocoagulation by diathermy, administered alone or with another intervention, versus comparators, in people with liver metastases, regardless of the location of the primary tumour. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We assessed risk of bias of the included trial using predefined risk of bias domains, and presented the review results incorporating the certainty of the evidence using GRADE. MAIN RESULTS: We included one randomised clinical trial with 306 participants (175 males; 131 females) who had undergone resection of the sigmoid colon, and who had five or more visible and palpable hepatic metastases. The diagnosis was confirmed by histological assessment (biopsy) and by carcinoembryonic antigen (CEA) level. The trial was conducted in Iraq. The age of participants ranged between 38 and 79 years. The participants were randomised to four different study groups. The liver metastases were biopsied and treated (only once) in three of the groups: 75 received electrocoagulation by diathermy alone, 76 received electrocoagulation plus allopurinol, 78 received electrocoagulation plus dimethyl sulphoxide. In the fourth intervention group, 77 participants functioning as controls received a vehicle solution of allopurinol 5 mL 4 x a day by mouth; the metastases were left untouched. The status of the liver and lungs was followed by ultrasound investigations, without the use of a contrast agent. Participants were followed for five years. The analyses are based on per-protocol data only analysing 223 participants. We judged the trial to be at high risk of bias. After excluding 'nonevaluable patients', the groups seemed comparable for baseline characteristics. Mortality due to disease spread at five-year follow-up was 98% in the electrocoagulation group (57/58 evaluable people); 87% in the electrocoagulation plus allopurinol group (46/53 evaluable people); 86% in the electrocoagulation plus dimethyl sulphoxide group (49/57 evaluable people); and 100% in the control group (55/55 evaluable people). We observed no difference in mortality between the electrocoagulation alone group versus the control group (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.94 to 1.03; 113 participants; very low-certainty evidence). We observed lower mortality in the electrocoagulation combined with allopurinol or dimethyl sulphoxide group versus the control group (RR 0.87, 95% CI 0.80 to 0.95; 165 participants; low-certainty evidence). We are very uncertain regarding post-operative deaths between the electrocoagulation alone group versus the control group (RR 1.03, 95% CI 0.07 to 16.12; 152 participants; very low-certainty evidence) and between the electrocoagulation combined with allopurinol or dimethyl sulphoxide groups versus the control group (RR 1.00, 95% CI 0.09 to 10.86; 231 participants; very low-certainty evidence). The trial authors did not report data on number of participants with other adverse events and complications, recurrence of liver metastases, time to progression of liver metastases, tumour response measures, and health-related quality of life. Data on failure to clear liver metastases were not provided for the control group. There was no information on funding or conflict of interest. We identified no ongoing trials. AUTHORS' CONCLUSIONS: The evidence on the beneficial and harmful effects of electrocoagulation alone or in combination with allopurinol or dimethyl sulphoxide in people with liver metastases is insufficient, as it is based on one randomised clinical trial at low to very low certainty. It is very uncertain if there is a difference in all-cause mortality and post-operative mortality between electrocoagulation alone versus control. It is also uncertain if electrocoagulation in combination with allopurinol or dimethyl sulphoxide may result in a slight reduction of all-cause mortality in comparison with a vehicle solution of allopurinol (control). It is very uncertain if there is a difference in post-operative mortality between the electrocoagulation combined with allopurinol or dimethyl sulphoxide group versus control. Data on other adverse events and complications, failure to clear liver metastases or recurrence of liver metastases, time to progression of liver metastases, tumour response measures, and health-related quality of life were most lacking or insufficiently reported for analysis. Electrocoagulation by diathermy is no longer used in the described way, and this may explain the lack of further trials.


Assuntos
Neoplasias do Colo , Eletrocoagulação/métodos , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Alopurinol/administração & dosagem , Causas de Morte , Dimetil Sulfóxido/administração & dosagem , Eletrocoagulação/mortalidade , Feminino , Humanos , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Solventes/administração & dosagem
9.
Chemosphere ; 263: 127907, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32835972

RESUMO

Electrocoagulation (EC) process is found as effective water and wastewater treatment method, as it can able to remove a variety of pollutants, treat various industrial wastewater, and able to handle fluctuations in pollutant quality and quantity. The performance of EC process can be improved significantly in combination with degradation processes. Different combinations of EC process with Fenton, electro-Fenton, photo-Fenton, photocatalysis, sonochemical treatment, ozonation, indirect electrochemical oxidation, anodic oxidation and sulfate radical based advanced oxidation process are found very effective for the treatment of water and wastewater. Enhanced performance of EC process in combination with degradation process was reported in most of the articles.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Eletrocoagulação , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Sulfatos , Água
10.
Chemosphere ; 263: 128052, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297063

RESUMO

A novel electrocoagulation (EC) system for the treatment of produced water (PW), with a provision to shift polarity is designed with the aim of reducing the problems resulting from electrode passivation. The enhancement of performance in terms of the rate and completion of the pollutant removal, energy and electrode consumption, sludge formation and ultimately the operating cost has been investigated by performing statistically designed experiments using RSM. The switching mode operation of EC had brought about significant improvement in the oil removal than the conventional mode. The polarity changeover in short span of batch recirculation time (BRT) was found to be more effective. Greater current density (CD) and supporting electrolyte concentration (SC) were found to enable a still lower switchover time (SOT) so that changeover frequency can further be increased. It was possible to remove a maximum of 99% COD and 98% Oil & Grease from a PW sample having initial concentration of 360 mgL-1of oil (1280 mgL- 1COD) at BRT of 15 min, CD of 1.6 Adm-2, SC of 3 gL-1 and SOT of 1 min. The combination of operating variables (BRT- 3 min, CD- 2.14 Adm-2SC- 3 gL-1and SOT- 1.9 min) giving minimum operating cost (0.65 US$/kg COD removed) achieving oil removal (88%) meeting discharge standards was found out by optimizing the RSM models for cost and oil removal. The method can be considered as an effective alternative for treating PW especially in offshore oil basins where time and space are the major constraints.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Eletrocoagulação , Eletrodos , Concentração de Íons de Hidrogênio , Esgotos , Eliminação de Resíduos Líquidos , Água
11.
Chemosphere ; 263: 128253, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297198

RESUMO

Co-occurrence of arsenic and anions in groundwater causes a severe health problems and combine effects of these pollutants significantly affect performance of treatment process. Thus, this study has been conducted to examine the combine effects of anions on arsenic removal using aerated electrocoagulation (EC) reactor with 3D Al electrodes in groundwater. A 3-level, six factors Box-Behnken experimental design (BBD) was applied to investigate the individual and combine effect of anions and operating time: phosphate (x1: 1-10 mg L-1), silica (x2: 20-80 mg L-1), bicarbonate (x3: 130-670 mg L-1), fluoride (x4: 2-10 mg L-1), boron (x5: 5-10 mg L-1), and operating time (x6: 8-22 min) on desired responses. The specified responses were effluent arsenic concentration (Cf,As), removal efficiency of arsenic (Re), consumptions of energy and electrode (ENC and ELC), operational cost (OC), and adsorption capacity (qe). The optimum operating parameters predicted using BBD were found to be x1: 1.0 mg L-1, x2: 26.0 mg L-1, x3: 651.5 mg L-1, x4: 2.0 mg L-1, x5: 9.9 mg L-1, and x6: 10.5 min considering highest removal efficiency of arsenic and lowest operational cost. Under these operating conditions, the experimental values of Cf,As, Re, ENC, ELC, OC, and qe were found to be 2.82 µg L-1, 98.6%, 0.411 kWh m-3, 0.0124 kg m-3, 0.098 $ m-3, and 17.65 µg As (mg Al)-1, respectively. Furthermore, mathematical modelling was conducted using quadratic regression model and response surface analysis was performed to understand the relationship between independent parameters and responses.


Assuntos
Arsênico , Água Subterrânea , Poluentes Químicos da Água , Purificação da Água , Eletrocoagulação , Eletrodos
12.
Chemosphere ; 263: 128314, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297249

RESUMO

Electrochemical processes are a promising alternative to traditional water treatment systems because they have advantages than conventional techniques such as chemical storage, small treatment systems, no alkalinity depletion, remote adjustment, and cost-effectiveness. The most crucial electrochemical method is Electrocoagulation (EC). Through creating cationic species, the EC causes the neutralization of pollutant surface charges and destabilizes suspended, emulsified or dissolved contaminants led to attracting particles of opposite charge and form flocculants. The main drawback of the EC process is a passive film forming on the electrode surface over time. Ultrasonic (US) waves breaking down sediments formed at the electrode surface and generate high amounts of radical species to remove pollutants by creating high-pressure points inside the solution during the cavitation phenomenon. Although EC systems are considered as an exemplary renaissance in water and wastewater treatment, various parameters related to these types of systems in pollutant degradation have not been fully addressed. To present a comprehensive vision of the current state of the art, and progress the treatment efficiency and agitate new studies in these fields, this review aimed to provide an overview of electrocoagulation's application in pollutant degradation, besides the advantages, associated disadvantages and further strategies for improving the performance of this technique. Moreover, this review discussed various parameters affecting the EC/US process, including nanoparticles addition, electrolyte concentration, current intensity, electrode distance, temperature, oxidant addition, pH, pollutant concentration, reaction time, and electrode combination, chloride addition, and ultrasonic frequency. Also, the efficiency of the EC/US process for disinfection, as well as treatment of car-washing, textile, pulp, and paper industry, oily, brewery wastewater, surfactant, humic acid, and heavy metals, are addressed.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Purificação da Água , Eletrocoagulação , Eletrodos , Eliminação de Resíduos Líquidos , Águas Residuárias
13.
Chemosphere ; 263: 128370, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297281

RESUMO

This work focuses on the removal of cyanide, chemical oxygen demand (COD), biological oxygen demand (BOD), and chloride from biological oxidation treated (BOT) effluent of the steel industry by integrated ozonation assisted electrocoagulation method. The removal efficiency of the pollutants was found to be inefficient when the electrocoagulation or ozonation process was performed separately. However, a combination of ozonation and electrocoagulation gives a highly satisfactory result. Such an integrated approach for the treatment of BOT effluent has not been previously investigated. The effects of operating variables viz. ozone generation rate, current density, and analysis time on pollutant removal were primarily analyzed for the hybrid process. The experimental operating condition was optimized and was seen that ozone generation rate of 1.33 mg s-1, ozonation time of 40 min, a current density of 100 A m-2, and electrolysis time of 30 min were sufficient for reducing the pollutant concentration below its permissible limits. The removal efficiencies of the combined process at optimum conditions were 99.8%, 94.7%, 95%, and 46.5% for cyanide, COD, BOD, and chloride ions, respectively. A kinetic study was performed for the degradation of the pollutants during ozonation. The pseudo-first-order kinetic model was found to be best suited for the analysis with the highest R2 value of 0.99 for cyanide, COD, BOD, and chloride, respectively. The mass transfer study conducted further showed that the volumetric mass transfer coefficient, Kla, was increased with that of the ozone generation rate. Cost estimation of the hybrid process was done and compared with that of the other reported integrated process.


Assuntos
Ozônio , Poluentes Químicos da Água , Cianetos , Eletrocoagulação , Resíduos Industriais , Aço , Eliminação de Resíduos Líquidos , Águas Residuárias
14.
Water Res ; 188: 116500, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33059157

RESUMO

In this paper we analyse the feasibility of low voltage iron electrocoagulation as a means of municipal secondary effluent treatment with a focus on removal of microbial indicators, Antibiotic Resistant Bacteria (ARB) and nutrients. A laboratory scale batch unit equipped with iron electrodes was used on synthetic and real secondary effluent from a municipal wastewater treatment plant. Synthetic secondary effluent was separately assayed with spiked Escherichia coli WR1 and with bacteriophage ΦX174, while real effluent samples were screened before and after treatment for E. coli, Extended Spectrum Betalactamase-producing E. coli, Enterococci, Vancomycin Resistant Enterococci, Clostridium perfringens spores and somatic coliphages. Charge dosage (CD) and charge dosage rate (CDR) were used as the main process control parameters. Experiments with synthetic secondary effluent showed >4log10 and >5log10 removal for phage ΦX174 and for E. coli WR1, respectively. In real effluents, bacterial indicator removal exceeded 3.5log10, ARB were removed below detection limit (≥2.5log10), virus removal reached 2.3log10 and C. perfringens spore removal exceeded 2.5log10. Experiments in both real and synthetic wastewater showed that bacterial removal increased with increasing CD and decreasing CDR. Virus removal increased with increasing CD but was irresponsive to CDR. C. perfringens spore removal increased with increasing CD yet reached a removal plateau, being also irresponsive to CDR. Phosphate removal exceeded 99%, while total nitrogen and chemical oxygen demand removal were below 15% and 58%, respectively. Operational cost estimates were made for power and iron plate consumption, and were found to be in the range of 0.01 to 0.24€/m3 for the different assayed configurations. In conclusion, low voltage Fe-EC is a promising technology for pathogen reduction of secondary municipal effluents, with log10 removals comparable to those achieved by conventional disinfection methods such as chlorination, UV or ozonation.


Assuntos
Águas Residuárias , Purificação da Água , Antagonistas de Receptores de Angiotensina , Inibidores da Enzima Conversora de Angiotensina , Antibacterianos , Bactérias , Eletrocoagulação , Escherichia coli , Indicadores e Reagentes , Ferro , Eliminação de Resíduos Líquidos , Microbiologia da Água
15.
Water Res ; 188: 116531, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33126004

RESUMO

Arsenic (As) is a toxic element present in many (ground)water sources in the world. Most conventional As removal techniques require pre-oxidation of the neutral arsenite (As(III)) species to the negatively charged arsenate (As(V)) oxyanion to optimize As removal and minimize chemical use. In this work, a novel, continuous-flow As removal system was developed that combines biological As(III) oxidation by bacteria with Fe electrocoagulation (EC), an Fe(0)-based electrochemical technology that generates reactive Fe(III) precipitates to bind As. The bio-integrated FeEC system (bio-FeEC) showed effective oxidation and removal of 150 µg/L As(III), without the need of chemicals. To remove As to below the WHO guideline of 10 µg/L, 10 times lower charge dosage was required for the bio-FeEC system compared to conventional FeEC. This lower Fe dosage requirement reduced sludge production and energy consumption. The As(III) oxidizing biomass was found to consist of bacteria belonging to Comamonadaceae, Rhodobacteraceae and Acidovorax, which are capable of oxidizing As(III) and are common in drinking water biofilms. Characterization of the As-laden Fe solids by X-ray absorption spectroscopy indicated that both bio-FeEC and conventional FeEC produced solids consistent with a mixture of lepidocrocite and 2-line ferrihydrite. Arsenic bound to the solids was dominantly As(V), but a slightly higher fraction of As(V) was detected in the bio-FeEC solids compared to the conventional FeEC.


Assuntos
Arsênico , Produtos Biológicos , Água Subterrânea , Poluentes Químicos da Água , Purificação da Água , Eletrocoagulação , Compostos Férricos , Ferro , Oxirredução
16.
J Clin Neurosci ; 82(Pt A): 71-75, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33317742

RESUMO

PURPOSE: To introduce a tooth-supported personalized template-assisted foramen ovale (FO) puncture system for trigeminal neuralgia (TN) treatment, analyze its advantages, and review other previously reported methods. METHODS: Sixty-seven patients were included. According to the preoperative digital design, the personalized puncture path was determined. Then, a tooth-supported personalized template was designed and manufactured. Finally, surgery (radiofrequency thermocoagulation or balloon compression) was carried out with the assistance of the template. The puncture effect and puncture-associated complications were evaluated, and the related literature was reviewed. RESULTS: The FO was successfully punctured in one attempt in all patients. The procedure was completed in 15 s in 35 (52.24%) patients and in 15-30 s in 28 (41.79%) patients. The required position was accurately reached in all patients, and the center point error range was within 1 mm. No complications associated with puncture occurred. CONCLUSION: The tooth-supported personalized template-assisted FO puncture system reported in this paper is an exceedingly simple, highly effective and safe FO puncture method that is worth popularizing.


Assuntos
Desenho de Equipamento , Forame Oval/cirurgia , Medicina de Precisão/métodos , Punções/métodos , Cirurgia Assistida por Computador/métodos , Neuralgia do Trigêmeo/cirurgia , Idoso , Oclusão com Balão/métodos , Eletrocoagulação/métodos , Feminino , Humanos , Pessoa de Meia-Idade , Impressão Tridimensional
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 6062-6065, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019353

RESUMO

Electrosurgery is used in the operating room on a daily basis as a means to cut tissue and maintain hemostasis. The principle of this technology lies in the transfer of electricity from an electrosurgical unit to the operating site on a patient's body and modifying the waveform of that electricity to achieve the desired surgical effect. Bipolar cautery uses two electrodes, an active and a return, both at the surgical site to perform electrosurgery. Bipolar cautery can be very useful in helping surgeons to operate; however, current designs are not well suited to a 2.1 mm working channel in endoscopic procedures due to their rigid structure, limited range of motion, and bulky design. This paper describes a novel approach to designing a minimally- invasive bipolar cautery tool suitable for flexible neuroendoscopy. The system features 1.9 mm diameter bipolar tips which resemble grasping forceps, making it easier for surgeons to hold tissue while performing electrosurgery. The electrode wires also function as the actuating cables used to open and close the tips, which require 2.10 mm to open the tips to 30.9 °. The results show that the tool can safely cauterize a porcine brain specimen at various settings on the electrosurgical unit, and increasing the setting increases the area of tissue affected by the electricity. Repeatability was demonstrated and exhaustion was reached after the tool was opened and closed 73 times. Future work will involve improving the current design to increase the number of cycles the tool can survive before losing function.


Assuntos
Neuroendoscopia , Animais , Eletrocoagulação , Eletrocirurgia , Humanos , Neuroendoscópios , Instrumentos Cirúrgicos , Suínos
18.
Cochrane Database Syst Rev ; 10: CD011031, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33095458

RESUMO

BACKGROUND: Endometriosis is associated with pain and infertility. Surgical interventions aim to remove visible areas of endometriosis and restore the anatomy. OBJECTIVES: To assess the effectiveness and safety of laparoscopic surgery in the treatment of pain and infertility associated with endometriosis. SEARCH METHODS: This review has drawn on the search strategy developed by the Cochrane Gynaecology and Fertility Group including searching the Cochrane Gynaecology and Fertility Group's specialised register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, reference lists for relevant trials, and trial registries from inception to April 2020. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) that compared the effectiveness and safety of laparoscopic surgery with any other laparoscopic or robotic intervention, holistic or medical treatment, or diagnostic laparoscopy only. DATA COLLECTION AND ANALYSIS: Two review authors independently performed selection of studies, assessment of trial quality and extraction of relevant data with disagreements resolved by a third review author. We collected data for the core outcome set for endometriosis. Primary outcomes included overall pain and live birth. We evaluated the quality of evidence using GRADE methods. MAIN RESULTS: We included 14 RCTs. The studies randomised 1563 women with endometriosis. Four RCTs compared laparoscopic ablation or excision with diagnostic laparoscopy only. Two RCTs compared laparoscopic excision with diagnostic laparoscopy only. One RCT compared laparoscopic ablation or excision with laparoscopic ablation or excision and uterine suspension. Two RCTs compared laparoscopic ablation and uterine nerve transection with diagnostic laparoscopy only. One RCT compared laparoscopic ablation with diagnostic laparoscopy and gonadotropin-releasing hormone (GnRH) analogues. Two RCTs compared laparoscopic ablation with laparoscopic excision. One RCT compared laparoscopic ablation or excision with helium thermal coagulator with laparoscopic ablation or excision with electrodiathermy. One RCT compared conservative laparoscopic surgery with laparoscopic colorectal resection of deep endometriosis infiltrating the rectum. Common limitations in the primary studies included lack of clearly described blinding, failure to fully describe methods of randomisation and allocation concealment, and poor reporting of outcome data. Laparoscopic treatment versus diagnostic laparoscopy We are uncertain of the effect of laparoscopic treatment on overall pain scores compared to diagnostic laparoscopy only at six months (mean difference (MD) 0.90, 95% confidence interval (CI) 0.31 to 1.49; 1 RCT, 16 participants; very low quality evidence) and at 12 months (MD 1.65, 95% CI 1.11 to 2.19; 1 RCT, 16 participants; very low quality evidence), where a positive value means pain relief (the higher the score, the more pain relief) and a negative value reflects pain increase (the lower the score, the worse the increase in pain). No studies looked at live birth. We are uncertain of the effect of laparoscopic treatment on quality of life compared to diagnostic laparoscopy only: EuroQol-5D index summary at six months (MD 0.03, 95% CI -0.12 to 0.18; 1 RCT, 39 participants; low quality evidence), 12-item Short Form (SF-12) mental health component (MD 2.30, 95% CI -4.50 to 9.10; 1 RCT, 39 participants; low quality evidence) and SF-12 physical health component (MD 2.70, 95% CI -2.90 to 8.30; 1 RCT, 39 participants; low quality evidence). Laparoscopic treatment probably improves viable intrauterine pregnancy rate compared to diagnostic laparoscopy only (odds ratio (OR) 1.89, 95% CI 1.25 to 2.86; 3 RCTs, 528 participants; I2 = 0%; moderate quality evidence). We are uncertain of the effect of laparoscopic treatment compared to diagnostic laparoscopy only on ectopic pregnancy (MD 1.18, 95% CI 0.10 to 13.48; 1 RCT, 100 participants; low quality evidence) and miscarriage (MD 0.94, 95% CI 0.35 to 2.54; 2 RCTs, 112 participants; low quality evidence). There was limited reporting of adverse events. No conversions to laparotomy were reported in both groups (1 RCT, 341 participants). Laparoscopic ablation and uterine nerve transection versus diagnostic laparoscopy We are uncertain of the effect of laparoscopic ablation and uterine nerve transection on adverse events (more specifically vascular injury) compared to diagnostic laparoscopy only (OR 0.33, 95% CI 0.01 to 8.32; 1 RCT, 141 participants; low quality evidence). No studies looked at overall pain scores (at six and 12 months), live birth, quality of life, viable intrauterine pregnancy confirmed by ultrasound, ectopic pregnancy and miscarriage. Laparoscopic ablation versus laparoscopic excision There was insufficient evidence to determine whether there was a difference in overall pain, measured at 12 months, for laparoscopic ablation compared with laparoscopic excision (MD 0.00, 95% CI -1.22 to 1.22; 1 RCT, 103 participants; very low quality evidence). No studies looked at overall pain scores at six months, live birth, quality of life, viable intrauterine pregnancy confirmed by ultrasound, ectopic pregnancy, miscarriage and adverse events. Helium thermal coagulator versus electrodiathermy We are uncertain whether helium thermal coagulator compared to electrodiathermy improves quality of life using the 30-item Endometriosis Health Profile (EHP-30) at nine months, when considering the components: pain (MD 6.68, 95% CI -3.07 to 16.43; 1 RCT, 119 participants; very low quality evidence), control and powerlessness (MD 4.79, 95% CI -6.92 to 16.50; 1 RCT, 119 participants; very low quality evidence), emotional well-being (MD 6.17, 95% CI -3.95 to 16.29; 1 RCT, 119 participants; very low quality evidence) and social support (MD 5.62, 95% CI -6.21 to 17.45; 1 RCT, 119 participants; very low quality evidence). Adverse events were not estimable. No studies looked at overall pain scores (at six and 12 months), live birth, viable intrauterine pregnancy confirmed by ultrasound, ectopic pregnancy and miscarriage. AUTHORS' CONCLUSIONS: Compared to diagnostic laparoscopy only, it is uncertain whether laparoscopic surgery reduces overall pain associated with minimal to severe endometriosis. No data were reported on live birth. There is moderate quality evidence that laparoscopic surgery increases viable intrauterine pregnancy rates confirmed by ultrasound compared to diagnostic laparoscopy only. No studies were found that looked at live birth for any of the comparisons. Further research is needed considering the management of different subtypes of endometriosis and comparing laparoscopic interventions with lifestyle and medical interventions. There was insufficient evidence on adverse events to allow any conclusions to be drawn regarding safety.


Assuntos
Endometriose/cirurgia , Infertilidade Feminina/cirurgia , Laparoscopia , Antineoplásicos Hormonais/uso terapêutico , Denervação/métodos , Eletrocoagulação/métodos , Endometriose/complicações , Endometriose/diagnóstico , Feminino , Gosserrelina/uso terapêutico , Hélio/uso terapêutico , Humanos , Infertilidade Feminina/etiologia , Dor Pélvica/etiologia , Dor Pélvica/cirurgia , Gravidez , Taxa de Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Útero/inervação
19.
Water Sci Technol ; 82(1): 56-66, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32910792

RESUMO

The use of the pulsed current can be an alternative to decrease the electrode polarization, as well as achieving lower energy consumption. This study investigated the electrocoagulation through pulsed current for the removal of natural organic matter from water. The experiments were carried out using Box-Behnken factorial design with the response surface methodology for the design of experiments, modeling and interpreting of the results. The electrocoagulation cell consisted of an acrylic reactor with 4 L capacity with four electrodes of aluminum, in parallel connection mode. The experimental independent variables studied were: current density (5.5 to 44.5 A m-2), electrodes spacing (2 to 7.6 mm), stirring rate (200 to 1,000 rpm), frequency (500 to 5,000 Hz), humic acid concentration (5 to 20 mg L-1) and NaCl (100 to 300 mg L-1) as supporting electrolyte, evaluating the residual apparent color (RAC) and electric energy consumption (EEC). The pH of the solution increased during the experiments, reaching basic values. The response surface regression procedure was employed to fit the second-order polynomial, and the model fitted well to the obtained values, reaching R2 0.9995 (RAC) and R2 0.9989 (EEC). The lowest RAC was 11.8 Hazen units (96.2% color removal), where the EEC was 0.393 kWh m-3.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Eletrocoagulação , Eletrodos , Água
20.
Pain Physician ; 23(4S): S295-S304, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32942789

RESUMO

BACKGROUND: Knee osteoarthritis (KOA) is characterized by the clinical symptoms of chronic knee pain and knee dysfunction, leading to disability and influencing the quality of life in severe cases. Radiofrequency treatment is a new method to reduce KOA-related pain and partially improve knee joint dysfunction without adverse effect. OBJECTIVE: The present study aimed to assess the treatment efficacy of radiofrequency thermocoagulation on the genicular nerve (RFTGN) and intraarticular pulsed radiofrequency (IAPRF) for KOA. STUDY DESIGN: Retrospective comparative study design. SETTING: This study took place at Shengjing Hospital of China Medical University. METHOD: KOA patients were randomly assigned to the RFTGN, IAPRF, and intraarticular steroid injection (IAS) groups. All procedures were performed under the guidance of computed tomography (CT). The observation indicators of this study were the numeric rating scale (NRS), Oxford knee scale (OKS), and perceived global effect (GPE). The time points for the assessment were 1-week, 1-month, 3-months, and 6-months after the treatment. RESULTS: The postoperative NRS scores in the 3 groups decreased significantly at all the observation time points as compared to the pretreatment scores (P < 0.05). For the patients in the IAS group, the analgesic effect was in a rebound trend, which was the best at 1-week posttreatment, and was close to the preoperative level at 6-months posttreatment. The short-term (1 week or 1 month) analgesic effect of the RFTGN group was better than that of the IAPRF group, and was similar in the long-term (3 or 6 months). The long-term analgesic effect of RFTGN and IAPRF groups was better than that of IAS group. The results of the OKS score were similar to the NRS score. The RFTGN group showed markedly improved knee function in the long-term than the IAPRF and IAS groups. The short-term treatment satisfaction was similar in each group, and some differences were detected between the groups with respect to long-term treatment satisfaction. LIMITATION: This study was a single-center retrospective study with a relatively small sample cohort and short follow-up periodCONCLUSION: Both RFTGN and IAPRF could alleviate the knee joint pain and improve the knee joint dysfunction; however, the treatment efficacy of RFTGN was better than that of IAPRF.


Assuntos
Betametasona/uso terapêutico , Eletrocoagulação/métodos , Osteoartrite do Joelho/terapia , Tratamento por Radiofrequência Pulsada/métodos , Terapia por Radiofrequência/métodos , Corticosteroides/uso terapêutico , Idoso , China , Feminino , Humanos , Injeções Intra-Articulares , Masculino , Pessoa de Meia-Idade , Manejo da Dor/métodos , Qualidade de Vida , Estudos Retrospectivos , Resultado do Tratamento
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