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1.
Sci Total Environ ; 752: 141713, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892041

RESUMO

Olive mill wastewater (OMW) is nowadays considered as a serious source pollution. At the same time, it contains high amounts of nutrients, especially potassium and phosphorus that could be recovered for agricultural purposes. The aim of the current experimental research work is to investigate the agronomic potential use of OMW based biochar produced from the slow pyrolysis at 500 °C of raw cypress sawdust (CS) impregnated with OMW (ICS-OMW-B). In order to understand the contribution of OMW, two additional biochars were produced from raw cypress sawdust (RCS-B) and cypress sawdust pretreated with potassium chloride (ICS-K-B). Results indicated that RCS impregnation by OMW significantly improved the produced biochar's chemical properties, especially its nutrients contents. Furthermore, in comparison with the other biochars, ICS-OMW-B application as an organic fertilizer showed promising results in terms of produced fresh and dry masses, as well as potassium bioavailability as assessed in test experiments with ryegrass. For instance, the dry matter masses of the rye-grass treated with ICS-OMW-B were about 23, 34 and 50 wt% higher than the ones measured for the tests using RCS-B, ICS-K-B and synthetic K-fertilizer as amendments, respectively. Besides, this biochar has a potential effect on the suppression of various pathogens existing in the tested agricultural soil. All these results demonstrated that the biochar generated from the slow pyrolysis of impregnated sawdust with OMW could be considered as attractive and promising organic fertilizer for acidic agricultural soils.


Assuntos
Cupressus , Olea , Carvão Vegetal , Resíduos Industriais/análise , Azeite de Oliva , Solo , Águas Residuárias
2.
An Acad Bras Cienc ; 92(3): e20200974, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33175018

RESUMO

The use of industrial waste as an additive in soil improvement has many advantages, including recycling of waste, reducing the need for waste storage, and obtaining an economical material. With the use of these wastes, desired positive results are obtained in some geotechnical properties of soil. However, the wastes can create trace element contamination in soil and groundwater. In this study, trace elements originating from industrial wastes contaminating groundwater are investigated. The industrial wastes were mixed at different proportions with the soil. These mixtures were compacted into a permeameter cells, and a seepage tests were performed. The leachates obtained from seepage tests were analyzed with inductively coupled plasma mass spectrometry (ICP-MS) to determine trace elements. The measured trace element quantities were compared with the allowable values in the relevant standards (EPA 822, WHO, TS266). The results reveal that quantitative values of the trace elements from the leachates were within the allowable limits, except for arsenic and chromium. Furthermore, when fly ash is used As and Cr can be combined with ettringite and be immobilized. Boron and silica fume are hazardous substances caused by trace elements. However, considering its long-term effect, they can be used with fly ash.


Assuntos
Arsênico , Oligoelementos , Arsênico/análise , Cinza de Carvão/análise , Resíduos Industriais/análise , Solo , Oligoelementos/análise
3.
J Environ Qual ; 49(3): 712-722, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016406

RESUMO

Chromite ore processing residue (COPR) is a waste derived from the chromate extraction from roasted ores and is deposited in some countries in landfills. The objective of this study was to investigate the leaching characteristics of hexavalent Cr [Cr(VI)] from two COPR samples obtained from unlined landfills in the Kanpur area of northern India. Column experiments were conducted under water-saturated conditions to simulate Cr release from the wastes caused by tropical heavy-rain events. Leached Cr(VI) decreased from 1,800 to 300 mg L-1 (Rania site) and 1,200 to 163 mg L-1 (Chhiwali site) during exchange of 12 pore volumes, which approximately corresponds to 2 yr of monsoon precipitation. Flow interruptions for 10, 100, and 1,000 h had little effect on Cr(VI) concentrations in the leachate, suggesting that Cr(VI) leaching was not limited by slow release kinetics. Calcium aluminum chromium oxide hydrates (CAC), and highly soluble phases such as Na2 CrO4 may play a role in controlling Cr(VI) concentration in the leachates. The amount of Cr(VI) leached from the columns accounted for 16% of the total Cr(VI) present in both COPR samples. A decrease in the solid-phase Cr(VI)/Crtotal ratio along the column was identified by X-ray absorption near edge structure (XANES) spectroscopy. Consistently, the smallest Cr(VI)/Crtotal ratios were found in the lower column section closest to the inflow. Our results suggest that Cr(VI) leaching from the unlined COPR landfills will continue for centuries, highlighting the urgent need to remediate these dumpsites.


Assuntos
Cromo/análise , Resíduos Industriais/análise , Índia , Espectroscopia por Absorção de Raios X
4.
Environ Sci Pollut Res Int ; 27(34): 43403-43411, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011942

RESUMO

The pulp bleaching process removes or transforms the chromophore groups in the pulp, so that the final product reaches a desired brightness. However, this chemical treatment inevitably results in yield loss. Therefore, the objective of this work was to quantify the yield loss caused during the bleaching of kraft pulp of Pinus radiata delignified with oxygen. The material was submitted to three distinct ECF sequences (D0(EPO)D1D2, D0(EPO)D1P, and Z/EDP). At the end of each bleaching stage, the pulp brightness and the loss of gravimetric yield of the process were determined, and the generated filtrates were collected. From these filtrates, the pollutant load of the effluent was determined by measuring the content of total dissolved solids, the chemical oxygen demand, the concentration of total organic carbon carbon, and the adsorbable organic halogens. Among the whole sequences, the Z/EDP sequence had the lowest gravimetric yield, the highest pollutant load in the collected filtrate, and lowest potential for adsorbable organic halogens generation. There was good correlation between the loss of yield from the bleaching process and the organic load of the generated effluent; and among the techniques studied, the quantification of total organic carbon was the most appropriate method for the indirect quantification of the yield loss during the bleaching process of the studied material.


Assuntos
Oxigênio , Pinus , Análise da Demanda Biológica de Oxigênio , Ácido Hipocloroso , Resíduos Industriais/análise , Papel , Eliminação de Resíduos Líquidos
5.
Chemosphere ; 258: 127388, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947665

RESUMO

Microplastics enter natural water bodies by a variety of pathways, one of them being wastewater streams. The role of industrial wastewater in overall microplastic emissions has so far only been estimated, because access is usually restricted. This is the first report providing quantitative data on microplastics in industrial wastewaters. The wastewater discharge of three different industrial sites was sampled in the size ranges of small microplastics (10-1000 µm) and large microplastics (1000-5000 µm). Differential scanning calorimetry (DSC) was used to detect and quantify semi-crystalline thermoplastics. Polyethylene (PE) and polypropylene (PP) were the most abundant polymers, but polyamide (PA) and polyethylene terephthalate (PET) were also found. As all three industrial sites had wastewater treatment plants (WWTP), the total concentrations were in the µg L-1 range, comparable to organic micropollutants in municipal WWTP effluents. At one industrial site, the removal capacity of the WWTP was evaluated by sampling and analyzing the influent as well as the effluent. The total microplastics concentration in the influent was in the g L-1 range, yielding a removal capacity of the industrial WWTP of >99.99 %.


Assuntos
Monitoramento Ambiental , Microplásticos/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Varredura Diferencial de Calorimetria , Resíduos Industriais/análise , Indústrias , Plásticos , Polietileno , Polímeros , Polipropilenos
6.
Ecotoxicol Environ Saf ; 203: 110991, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888602

RESUMO

The stimulant and toxicity effects of reported organic (acetic acid, propionic acid, butyric acid, formic acid, oil & grease) and inorganic (copper) by-products presented in palm oil mill effluent on anaerobic bacterial population were examined in this paper. The toxicity test had shown that acetic, propionic and butyric acids tend to stimulate the bacterial density level (survival rate more than 50%), while formic acid, copper, oil and grease were shown to have suppressed the density level (survival rate less than 50%). The highest biomass recorded was 1.66 mg/L for the concentration of acetic acid at 216 mg/L and lowest biomass concentration, 0.90 mg/L for copper at 1.40 mg/L. Biohydrogen-producing bacteria have a favourable growth rate around pH 5.5. The comparison of half maximal effective concentration (EC50) values between two test duration on the effects of organic and inorganic by-products postulate that bacteria had a higher tolerance towards volatile fatty acids. While acetic, butyric and propionic acids had exhibited higher tolerance EC50 values for bacteria, but the opposite trend was observed for formic acid, copper and oil & grease.


Assuntos
Bactérias Anaeróbias/efeitos dos fármacos , Óleo de Palmeira/toxicidade , Testes de Toxicidade/métodos , Relação Dose-Resposta a Droga , Hidrogênio/metabolismo , Resíduos Industriais/análise
7.
Environ Sci Pollut Res Int ; 27(34): 43372-43388, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32902753

RESUMO

The study aims to analyze and enhance the eco-efficiency of rice processing in Pakistan while focusing on pollution prevention, waste management, and valorization opportunities. Three rice mills were selected, and physical and chemical properties of their wastewater and solid waste were analyzed. It is depicted that rice husk has the highest share in the solid waste stream and possesses a significant renewable energy potential with a calorific value of 16 MJ/kg and a much lower energy cost of about 0.4 USD/MJ as compared to diesel and furnace oil, i.e., 36.8 and 26.2 USD/MJ, respectively. Recovery of commercially valuable by-products from the effluent of parboiling process is also investigated, and about 0.25 kg of starch/L from wastewater has been effectively reclaimed by wet milling method. The effluent water is also analyzed using Streeter-Phelps model which confirmed that value of contaminants in the wastewater of two of the selected rice mills exceeds the dilution capacity of the receiving body, with dissolved oxygen values at critical level as 0.54 mg/L and -20.7 mg/L respectively. Water pinch analysis and water cascade analysis (WCA) have also been employed to monitor and manage the water footprints. While the concentration composite curve depicted that about 0.8 ton/h of freshwater is saved by an application of smart water integration and pinch point was determined as 1814 ppm. While the WCA confirms that a total water demand of 45.3 kg/s at the third purity level has been reduced to 28.0 kg/s at the lowest purity level.


Assuntos
Oryza , Gerenciamento de Resíduos , Poluentes Químicos da Água , Resíduos Industriais/análise , Paquistão , Resíduos Sólidos , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
8.
Ecotoxicol Environ Saf ; 202: 110939, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800222

RESUMO

Pulp and paper mill wastewater (PPMWW) contains high concentrations of recalcitrant compounds that cause toxicity to organisms. Advanced oxidation processes (AOPs) have the ability to degrade these compounds and reduce overall toxicity. Physicochemical characterization and Lactuca sativa toxicity test were conducted to compare the effectiveness of two post-treatments: UV/H2O2 and photo-Fenton. A comparison of four phytotoxicity indexes was carried out. PPMWW from a Brazilian treatment plant was characterized by high values of phenols, color, integrated spectral area (ISA), and chemical oxygen demand (COD), and caused significant inhibition to seedling development. The use of both post-treatments allowed the removal of over 75% of phenols, color, ISA, and COD. Although UV/H2O2 was more effective in removing phenols and ISA, photo-Fenton better reduced phytotoxicity. The most sensitive phytotoxicity indexes were RGIC0.8 and GIC80%, whereas SGC0, REC-0.25 and REC-0.50 better showed the effectiveness of the post-treatments. We suggest the combined use of two phytotoxicity indexes: one that evaluates the effects on seed germination and, another, on root elongation, e.g., SGC0 and RGIC0.8. Additionally, we recommend the use of ISA for monitoring programs of wastewater treatments because it is a cost-effective approach that allows narrowing down the search and identification of compounds present in complex mixtures.


Assuntos
Papel , Fenóis/toxicidade , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Brasil , Cor , Corantes/toxicidade , Peróxido de Hidrogênio/química , Resíduos Industriais/análise , Oxirredução , Fenóis/análise , Plantas/efeitos dos fármacos , Águas Residuárias/química
9.
Waste Manag ; 117: 32-41, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32805599

RESUMO

This study conducted a survey at 15 building construction and demolition sites in Hanoi, Vietnam in order to identify waste generation rates (WGR), composition, and current handling practices of construction and demolition waste (CDW). Waste quantification based on CDW layout, image analysis to identify CDW components, and face-to-face interviews with construction and demolition contractors to reveal CDW flows were performed. WGRs of 79.3 kg/m2 and 1,030 kg/m2 were determined in small- and large-scale construction sites, respectively, whilst WGRs at small and large demolition sites were 610 kg/m2 and 318 kg/m2. The composition analysis identified soil, concrete, and brick as the major CDW components, consistent with building structures in Vietnam. The interviews discovered that merely 10% of total CDW flows was from recycled and reused CDW. Reuse and recycling rates were most significant for metal and were lower (in descending order) for brick, concrete, and soil. These findings raise a need for aggressive and integrated strategies to promote more sustainable CDW management in the country, including the development of recycled CDW product standards, policies that facilitate recycling, and more importantly, a sustainable business model for CDW recycling, for which future evaluations of economic feasibility are of great importance.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Materiais de Construção , Resíduos Industriais/análise , Reciclagem , Vietnã
10.
Bioresour Technol ; 316: 123946, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32769001

RESUMO

The agri-food waste (AW) require amendments for composting to adjust nutritional and physicochemical deficiencies. The theoretical mixtures formulation is difficult to reach on an industrial scale. The main objective of this work was to evaluate to what extent the composition of AW-based mixtures determines the quality of the final compost produced at the industrial scale. Raw materials having the same AW share characteristics, irrespectively of the amendments added, but their compost were different. All the materials were biological stable at the cooling phase, and mature enough at the end, although the degree of humification did not match with the absence of phytotoxicity. The final compost had sufficient quality even though the AW-based raw materials have a low C/N ratio (<20) and other characteristics such as high electrical conductivity (13 mS·cm-1) and pH (<8.5) that are unfavorable for composting. The management operations during industrial composting correct the deficiencies of raw materials.


Assuntos
Compostagem , Eliminação de Resíduos , Carbono , Alimentos , Resíduos Industriais/análise , Nitrogênio/análise , Solo
11.
Waste Manag ; 117: 179-187, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32861080

RESUMO

Steel slags are generally alkaline with a high calcium content and are viewed as a potential feedstock for carbon dioxide sequestration and utilization, mostly through aqueous mineral carbonation routes. For recovery of multiple metals such as Ca, Fe, Mg, and Si, and generation of value-added products by dissolution and precipitation reactions in aqueous media, enhancing the metal selectivity and extraction efficiency are important. However, there is limited understanding of independent parameters that influence these important characteristics. In this work, a systematic attempt was made to correlate these key dissolution characteristics of basic oxygen furnace slag in acidic media with its mineralogical and physical characteristics, the changes in aqueous chemistry, and the role of potential secondary precipitates. The findings from this study substantiate that steel slag is a potential feedstock because of the calcium being mainly present as orthosilicates, which were found to leach congruently without forming a leached layer that might hinder calcium extraction. The leaching of Fe(II) from the slag is the main source of impurity and its slow oxidation-precipitation leads to a pH plateau at the end of the dissolution step. Oxidation-precipitation of Fe(II) is controlled by hydroxyl concentration in the aqueous solution, which necessitates a pH-swing step by addition of a base after dissolution. Use of surface complexing agents, such as sodium molybdate, can significantly reduce iron impurity in the leachate and obtain an iron-rich slag residue for recycle to iron and steel industry.


Assuntos
Resíduos Industriais/análise , Aço , Dióxido de Carbono , Metais , Solubilidade
12.
Chemosphere ; 261: 127689, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32736242

RESUMO

Distillery wastewater has significant amount of coloring compounds and organic substances even after the secondary treatment process, which poses many severe environmental and health threats. However, the recalcitrant coloured compounds have not yet been clearly identified. In this study, two bacterial strains DS3 and DS5 capable to decolorize distillery wastewater (DWW) pollutants were isolated and characterized as Staphylococcus saprophyticus (MF182113) and Alcaligenaceae sp. (MF182114), respectively. Results showed that mixed bacterial culture was found more effective decolorizing 71.83% DWW compared to axenic culture DS3 and DS5 resulting only 47.94% and 50.67% decolorization, respectively. The FT-IR and LC-MS/MS analysis of untreated DWW showed the presence of many recalcitrant compounds having different functional groups, but after bacterial treatment, most of compounds get diminished and the toxicity of DWW was reduced significantly. Further, the Nile red staining of Caenorhabditis elegans exposed to untreated and bacteria treated DWW for evaluation of toxicity assay and results revealed that the worms exposed to untreated DWW showed sharp reduction in total fat content having more profound effects, suggesting the diminished nAchR signaling as compare to bacterial treated DWW. Hence, this study revealed that inadequate disposal of untreated DWW may cause transfer of toxic substances into the environment and receiving water bodies.


Assuntos
Biodegradação Ambiental , Eliminação de Resíduos Líquidos/métodos , Animais , Bactérias/metabolismo , Caenorhabditis elegans/metabolismo , Cromatografia Líquida , Cor , Poluentes Ambientais/análise , Resíduos Industriais/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Espectrometria de Massas em Tandem , Águas Residuárias/análise , Poluentes Químicos da Água/análise
13.
Environ Sci Pollut Res Int ; 27(31): 39343-39353, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32648223

RESUMO

The leather industry is one of the major producers of wastewater, releasing large amounts of various chemicals into the environment. Chromium (Cr) is the most commonly used agent in the tanning industry. Accumulation in the animal body can adversely affect the functioning of animal tissues. The current study investigated the toxic effects of Cr on lung, kidney, liver, and testicular tissues in Libyan jirds (Meriones libycus) inhabiting the area surrounding Ghazghan leather industrial town, Mashhad, Iran. Average Cr concentrations were found to be significantly higher in samples from contaminated areas than controls (p < 0.05). The highest accumulation of Cr was found in lung tissue, while the liver tissue showed the lowest. The results also showed that sex and age had no significant effect on Cr accumulation in any tissue at either sampling area (p < 0.05). Histological analyses showed that Cr accumulation had caused changes in tissue samples from Libyan jirds from the contaminated area. Hyperemia was observed in all tissues. In kidney tissue, necrosis and degeneration of the epithelial cells of the tubules were seen as well, and in one case, we also observed hemorrhage. In liver tissue, necrosis, degeneration, and inflammation were observed, along with one case, of fibrosis. In lung tissue, we observed emphysema, hemorrhage, and inflammation. Testicular tissue also showed a considerable lesion. Given the proximity of specimens' habitat to an area of importance, i.e., the industrial town, and the species' dependence on its habitat for nutrition, Libyan jirds are particularly useful for monitoring. Thus, they can be used to monitor the level of contamination in future studies.


Assuntos
Cromo/análise , Indústrias , Animais , Gerbillinae , Resíduos Industriais/análise , Irã (Geográfico) , Curtume , Águas Residuárias/análise
14.
Environ Sci Pollut Res Int ; 27(32): 40088-40100, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32656751

RESUMO

Due to the complexity and variability of textile wastewater composition, a constant search for new treatment strategies that are efficient, eco-friendly, and cost-effective is mandatory. In the present study, the efficiency of coagulation-flocculation using biocoagulants derived from cactus Opuntia ficus indica and eggplant Solanum melongena to remove toxic compounds from Tunisian textile wastewater samples was evaluated by combining assays to investigate physicochemical properties and in vitro (geno)toxicity with analytical chemistry. Both natural coagulants could significantly improve the physicochemical properties of the textile wastewater samples compared to the traditionally used chemical coagulant. The highest rate of decolorization was achieved after treatment with the cactus-derived coagulant. The analytical study revealed the presence of only crystal violet dye (CV) in only one sample. Both natural coagulants were able to remove CV, which may (partially) explain the decolorization of the treated samples. Only one untreated textile effluent induced a genotoxic response in the VITOTOX® assay. The genotoxic effect was not linked to the presence of CV and was no longer observed after treatment with each of the natural coagulants, suggesting the effectiveness of the remediation treatments to remove potentially genotoxic compound(s). However, in the other genotoxicity tests, no biologically relevant effects were observed for any of the tested samples. In conclusion, although the physicochemical data indicate that the use of natural coagulants (cactus and eggplant) could be an interesting alternative treatment process to the chemical coagulant for detoxifying textile effluents, these results were only partially supported by the toxicological and analytical data.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Floculação , Resíduos Industriais/análise , Indústria Têxtil , Têxteis , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
15.
Environ Sci Pollut Res Int ; 27(32): 40101-40108, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32656754

RESUMO

The oily wastewater was treated by electrocoagulation with Fe78Si9B13 amorphous ribbons as anode and graphite plates as cathode under such processing parameters as different pH values and current density, respectively. The degradation effect on the oily wastewater was characterized by chemical demand oxygen (COD), while the ribbons before and after using were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicate that under the conditions of pH = 3 and current density being 3.125 A/cm2, the optimal COD removal efficiency was obtained to be 73.22%. Compared with the ordinary crystalline iron plate, the COD removal efficiency of resultant wastewater degraded by the amorphous ribbons is more than doubled. Simultaneously, the Fe78Si9B13 amorphous ribbons exhibit good structural stability even after four cycles of using.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Análise da Demanda Biológica de Oxigênio , Eletrocoagulação , Eletrodos , Concentração de Íons de Hidrogênio , Resíduos Industriais/análise , Óleos , Eliminação de Resíduos Líquidos
16.
Water Sci Technol ; 81(7): 1345-1353, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32616687

RESUMO

The present paper reveals results of research for cost-effective removal of chemical oxygen demand (COD) contained in industrial paper mill effluent. Not only process efficiency but also wastewater treatment costs are discussed. Different pre-treatment processes are applied aiming to investigate the COD removal before discharge to the municipal sewage network. The objective of this paper is to find the optimal operating conditions for the coagulation process. The effects of key operational parameters, including the type of coagulant, initial pH, temperature and coagulant dose, on COD percentage removal were investigated. The laboratory experiments confirmed the high efficiency of chemically enhanced mechanical treatment towards COD. The data obtained show that even low dose of chemicals provides sufficient COD reduction. The initial pH of the wastewater had a significant impact on the COD removal. Under the optimal operational conditions (pH = 7.5, T = 18 °C) the treatment of wastewater from paper industries by coagulation has led to a reduction of 70% COD for wastewater discharged. In terms of the investigated paper industry wastewater, polyaluminium chloride appears to be most suitable for treatment of high COD concentration. However, in an economic evaluation of requirements for wastewater treatment, operating costs and associated saving were such that PAX was more favourable.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias , Análise da Demanda Biológica de Oxigênio , Análise Custo-Benefício , Resíduos Industriais/análise
17.
J Chromatogr A ; 1623: 461200, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505289

RESUMO

Selectivity and high throughput are important for determination of trace level of various organophosphate flame retardants (OPFRs) in environmental matrices. In this work, three selective monolithic fibers for solid phase microextraction (SPME) were prepared and evaluated. They are graphene oxide (GO)-based surface trimethyl phosphate (TMP) imprinted polymeric fiber (GO/TMP-IPF), GO-based surface tri (2-chloroethyl) phosphate (TCEP) imprinted polymeric fiber (GO/TCEP-IPF) and GO-based surface triphenyl phosphate (TPhP) imprinted polymeric fiber (GO/TPhP-IPF). The imprinting factors of GO/TMP-IPF for TMP, GO/TECP-IPF for TCEP and GO/TPhP-IPF for TPhP were tested as high as 4.3, 4.5, 10.3, respectively. The three fibers were bound to a stainless steel wire to assemble a GO-based surface molecularly imprinted polymeric fiber array (GO/MIP-FA). GO/MIP-FA-SPME device was coupled to gas chromatography-flame photometric detector and carried out simultaneous determination of TMP, TCEP and TPhP in environmental water. Under the optimal conditions, ultralow limits of quantification (1.7 ng L-1-5.0 ng L-1); linearity (>0.99); intra- and inter-day precision expressed as relative standard deviations for an array in the range of 4.9-8.6% and 5.8-8.2%, respectively, and array-to-array reproducibility in the range of 7.2-9.1% were obtained. The GO/MIP-FA-SPME technique was successfully applied for the determination of OPFRs in various environmental water samples, and the relative recoveries were found to be in the range from 72.4 to 112.0%.


Assuntos
Retardadores de Chama/análise , Grafite/química , Impressão Molecular/métodos , Organofosfatos/análise , Polímeros/química , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Resíduos Industriais/análise , Cinética , Reprodutibilidade dos Testes , Temperatura
18.
Environ Sci Pollut Res Int ; 27(28): 35567-35579, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32594440

RESUMO

The wastewater pollution of tanneries is of high concern. The investigation of technologies to minimize the consumption of chemicals in the leather production process can reduce the environmental burden. We focus on the reduction of ammonium salts in the leather production process. Salt-free deliming of animal hides with compressed carbon dioxide as deliming agent is performed for the first time in a technical scale 20-L drum. As a result, CO2-deliming at 30 bar and 30 °C is two times faster than conventional deliming. In addition, the deliming efficiency is slightly improved. The initial calcium (Ca) content of the hides of 8 g/kg reaches the lowest value of 2 g/kg after a process time of 3 h. However, a process time of 60 min is sufficient to reach an elimination of 50 wt% of the initial lime. The resulting Ca-content of 4 g/kg after 60 min CO2-deliming at 30 bar is comparable with the Ca-content of conventional delimed hide. We clarify that the ampholytic character of the collagen itself enables a buffering of the pH-value at pH-7. The stable pH-value supports the selection of specific bating enzymes that decompose non-collagen proteins. No buffering salts contaminate the wastewater. The high-pressure CO2-deliming process has high potential to reduce wastewater emissions, save costs for chemicals, and process time in industrial beamhouse applications.


Assuntos
Resíduos Industriais/análise , Águas Residuárias , Animais , Dióxido de Carbono
19.
Chemosphere ; 258: 127325, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540541

RESUMO

This study investigates the effectivenesses of electrocoagulation, ultrasound, and ultrasound-assisted electrocoagulation processes for the removal of color and chemical oxygen demand (COD) from aqueous dye solutions. The coupling of electrocoagulation processes with ultrasound has been found useful for water and wastewater treatment in recent years. These experimental results demonstrate that ultrasound-assisted electrocoagulation processes provide greater color and COD removal than ultrasound or electrocoagulation processes alone. The optimum conditions for the combined process were found to be Fe-Fe-SS-SS/Al-Al-SS-SS (electrode connection type) in the monopolar electrode connection mode; 75 and 50 A m-2 (current density) for RR241 and DB 60, respectively, at a fixed frequency of 40 kHz; and an ultrasound power of 180 W in a 1 L aqueous solution. Under these optimum conditions, the color and COD removal efficiencies for an aqueous solution of 100 mg L-1 reached 99-99.9% and 100 - 100% for RR241 and DB 60, respectively. Complete removal was achieved for both COD and color by employing a combination of ultrasound-assisted electrocoagulation (US + EC) with only 4 min of electrolysis, while the traditional EC treatment achieved removal of approximately 87% of COD and 92% color for both dyes using the MP-P connection mode for 5 min. Conversely, ultrasound power alone removed approximately 34-60% of color and 30-36% of COD for RR241 and DB 60, respectively. Compared with the traditional EC treatment, the combination of ultrasound irradiation and electrocoagulation treatment significantly reduced electrode passivation and increased the removal of pollutants in shorter operation times.


Assuntos
Corantes , Resíduos Industriais/análise , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Cor , Eletrocoagulação/métodos , Eletrodos , Eletrólise/métodos , Concentração de Íons de Hidrogênio , Águas Residuárias , Água
20.
Chemosphere ; 258: 127271, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535444

RESUMO

Water and soil contamination by industrial wastes is a global concern. Biological treatment of industrial wastewater using bioreactors allows the removal of organic matter and nutrients and enables either reuse or safe discharge. Wastewater bioremediation depends in part on the microbial communities present in the bioreactor. To ascertain which communities may play a role in the remediation process, the present study investigates the microbial community structure and diversity of microorganisms found in a full-scale membrane bioreactor (MBR) for industrial wastewater treatment. The study was carried out using high-throughput data observations following a failure (crash) of the MBR and during the extended recovery of the process. Results revealed a positive correlation between the MBR's ability to remove organic matter and its microbial community richness. The significant changes in relative microbial abundance between crash and recovery periods of the MBR revealed the important role of specific bacterial genera in wastewater treatment processes. A whole-genome metagenomics based comparison showed a clear difference in microbial makeup between two functional periods of MBR activity. The crash period was characterized by abundance in bacteria belonging to Achromobacter, Acinetobacter, Halomonas, Pseudomonas and an uncultured MBAE14. The recovery period on the other hand was characterized by Aquamicrobium and by Wenzhouxiangella marina. Our study also revealed some interesting functional pathways characterizing the microbial communities from the two periods of bioreactor function, such as Nitrate and Sulfate reduction pathways. These differences indicate the connection between the bacterial diversity of the MBR and its efficiency to remove TOC.


Assuntos
Reatores Biológicos/microbiologia , Microbiota/efeitos dos fármacos , Águas Residuárias , Purificação da Água/métodos , Biodegradação Ambiental , Gammaproteobacteria/efeitos dos fármacos , Gammaproteobacteria/genética , Resíduos Industriais/análise , Membranas Artificiais , Metagenômica , Microbiota/genética , Esgotos/microbiologia , Águas Residuárias/química , Águas Residuárias/microbiologia
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