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1.
J Environ Manage ; 331: 117286, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36640645

RESUMO

Consideration is now being given to the use of metal coagulants to remove turbidity from drinking water and wastewater. Concerns about the long-term impact of non-biodegradable sludge on human health and the potential contamination of aquatic systems are gaining popularity. Recently, alternative biocoagulants have been suggested to address these concerns. In this study, using a 1 M sodium chloride (NaCl) solution, the active coagulating agent was extracted from Pinus halepensis Mill. Seed, and used for the first time to remove Congo red dye, the influence of numerous factors on dye removal was evaluated in order to make comparisons with conventional coagulants. The application of biocoagulant was shown to be very successful, with coagulant dosages ranging from 3 to 12 mL L-1 achieving up to 80% dye removal and yielding 28 mL L-1 of sludge. It was also found that biocoagulant is extremely pH sensitive with an optimum operating pH of 3. Ferric chloride, on the other hand, achieved similar removal rate with higher sludge production (46 mL L-1) under the same conditions. A Fourier Transform Infrared Spectroscopy and proximate composition analysis were undertaken to determine qualitatively the potential active coagulant ingredient in the seeds and suggested the involvement of proteins in the coagulation-flocculation mechanism. The evaluation criteria of the Support vector machine_Gray wolf optimizer model in terms of statistical coefficients and errors reveals quite interesting results and demonstrates the performance of the model, with statistical coefficients close to 1 (R = 0.9998, R2 = 0.9995 and R2 adj = 0.9995) and minimal statistical errors (RMSE = 0.5813, MSE = 0.3379, EPM = 0 0.9808, ESP = 0.9677 and MAE = 0.2382). The study findings demonstrate that Pinus halepensis Mill. Seed extract might be a novel, environmentally friendly, and easily available coagulant for water and wastewater treatment.


Assuntos
Pinus , Purificação da Água , Humanos , Vermelho Congo/análise , Esgotos/química , Pinus/química , Águas Residuárias , Floculação , Sementes/química , Purificação da Água/métodos , Cloreto de Sódio
2.
Molecules ; 28(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36615536

RESUMO

Iodinated X-ray contrast media (ICM) as emerging micropollutants have attracted considerable attention in recent years due to their high detected concentration in water systems. It results in environmental issues partly due to the formation of toxic by-products during the disinfection process in water treatment. Consequently, various approaches have been investigated by researchers in order to achieve ICM total mineralization. This review discusses the different methods that have been used to degrade them, with special attention to the mineralization yield and to the nature of formed by-products. The problem of pollution by ICM is discussed in the first part dedicated to the presence of ICM in the environment and its consequences. In the second part, the processes for ICM treatment including biological treatment, advanced oxidation/reductive processes, and coupled processes are reviewed in detail. The main results and mechanisms involved in each approach are described, and by-products identified during the different treatments are listed. Moreover, based on their efficiency and their cost-effectiveness, the prospects and process developments of ICM treatment are discussed.


Assuntos
Iodo , Poluentes Químicos da Água , Purificação da Água , Meios de Contraste , Raios X , Purificação da Água/métodos , Desinfecção , Poluentes Químicos da Água/análise
3.
Water Sci Technol ; 85(6): 1840-1854, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35358075

RESUMO

Iron alginate beads (Fe-Alg) were prepared, characterized and implemented for the degradation of amoxicillin (AMX) by the heterogeneous electro-Fenton process using a graphite cathode recovered from used batteries. Scanning electron microscopy (SEM) showed that (Fe-Alg) beads have a spherical shape and the results of energy dispersive spectrometric (EDS) revealed the presence of iron in (Fe-Alg). Optimization of the operating parameters showed that a complete degradation of AMX was achieved within 90 min of heterogeneous electro-Fenton treatment by operating under these conditions: initial AMX concentration: 0.0136 mM, I = 600 mA, [Na2SO4] = 50 mM, pH = 3, T = 25 °C, ω = 360 rpm. The corresponding chemical oxygen demand (COD) abatement was 50%. Increasing the contact time increased the COD abatement to 85.71%, after 150 min of heterogeneous electro-Fenton treatment. The results of the kinetic study by using nonlinear methods demonstrated that the reaction of AMX degradation obeyed to a pseudo-second-order kinetic. Iron content of 4.63% w/w was determined by the acid digestion method. After 5 cycles of use, the Alg-Fe catalyst depletion was only 8%. Biodegradability was remarkably improved after electro-Fenton pretreatment, since it increased from 0.07 initially to 0.36. The heterogeneous electro-Fenton process had efficiently eliminated AMX and it increased the biodegradability of the treated solution.


Assuntos
Grafite , Poluentes Químicos da Água , Alginatos/química , Amoxicilina , Eletrodos , Peróxido de Hidrogênio/química , Poluentes Químicos da Água/química
4.
Water Sci Technol ; 83(3): 622-630, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33600366

RESUMO

Aspergillus parasiticus (A. parasiticus) CBS 100926T was used as a biosorbent for the removal of Methylene Blue (MB), Congo Red (CR), Sudan Black (SB), Malachite Green Oxalate (MGO), Basic Fuchsin (BF) and Phenol Red (PR) from aqueous solutions. The batch biosorption studies were carried out as a function of dye concentration and contact time. The biosorption process followed the pseudo-first-order and the pseudo-second-order kinetic models and the Freundlich and Langmuir isotherm models. The resulting biosorbent was characterized by Scanning Electron Microscopy (SEM), X-Ray Diffractometer and Fourier Transformer Infrared Spectroscopy (FTIR) techniques. The results of the present investigation suggest that A. parasiticus can be used as an environmentally benign and low cost biomaterial for the removal of basic and acid dyes from aqueous solution.


Assuntos
Corantes , Poluentes Químicos da Água , Adsorção , Aspergillus , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
5.
Environ Sci Technol ; 54(1): 559-567, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31840997

RESUMO

The electrocatalytic activity of bismuth considered as a low-cost and green electrode material was studied in reductive dechlorination processes. Cyclic voltammetry analyses showed that the Bi electrode exhibited a high catalytic activity to reduce alachlor, a chlorinated herbicide, in the aqueous medium at different pH values. Bulk electrolyses were performed at different potentials and pH values. Alachlor was reduced in deschloroalachlor, its dechlorinated derivative, with a high selectivity (96%) and a current efficiency of 48%. The reductive dechlorination of other chlorinated compounds with an activated carbon atom was then studied, showing that the bismuth electrode catalyzed the electroreduction of chloroacetamides, α-halocarbonyl, and α-haloallyl pollutants. Cyclic voltammetry experiments allowed us to propose a mechanism explaining the high catalytic activity of bismuth to reduce these families of compounds.


Assuntos
Bismuto , Poluentes Ambientais , Eletrodos , Eletrólise , Halogenação
6.
Water Sci Technol ; 82(7): 1404-1415, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33079719

RESUMO

In this study, peroxydisulfate (PDS) was successfully activated by UV-irradiation for the degradation of paracetamol (PCT) frequently detected in the environment. Results showed that increasing the initial PDS concentration from 5 to 20 mM promote the removal of PCT from 49.3% to 97.5% after 240 min of reaction time. As the initial PCT concentration increased from 0.066 to 0.132 mM, the degradation efficiency of PCT decreased from 98% to 73% after 240 min of reaction time, while the optimal pH was found to be 6. It is apparent that the degradation rate of PCT was favored by the lamp power regardless of the initial PCT concentration, for 0.132 mM of PCT, the degradation efficiency increased from 73% to 95% when the lamp power increased from 9 to 30 W, respectively. The kinetic of degradation of the PCT was described by a pseudo-second order kinetic model. The model obtained by central composite design led to the following optimal conditions for PCT degradation: 0.132 mM initial PCT concentration, 20 mM PDS dose, pH solution 6 and lamp power 30 W led to the removal of 92% of PCT at 25 °C within 240 min of reaction time.


Assuntos
Acetaminofen , Poluentes Químicos da Água , Cinética , Sulfatos , Raios Ultravioleta , Poluentes Químicos da Água/análise
7.
Environ Monit Assess ; 192(5): 287, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32296943

RESUMO

The purpose of this study was to elucidate the capacity of a Pseudomonas aeruginosa strain to metabolize hydrocarbons sludge in the production of biosurfactants to fight against environmental threats. The performance of the treatment consisted in monitoring the inductive metabolism of the strain during 48 h at a temperature of 37 °C which constitutes an opportunity of treatment of various hydrocarbons contained in crude oil and spilled in the ecosystem to prevent pollution and damage. The results showed that a treatment rate of 96,8% and an emulsification index of 71.8% were obtained corresponding to a phosphate buffer concentration of 30 mmol/L. The main role of the biosurfactants produced was to emulsify the medium and to absorb the oils contained in the hydrocarbons sludge. This allowed to stabilize hydrocarbon oils and favored the inductive metabolism of P. aeruginosa. Furthermore, physicochemical and Fourier transform infrared spectroscopy (FTIR) analysis showed that the produced biosurfactants were of rhamnolipid type. They showed promising surfactant properties, such as a strong reduction in the surface tension of water from 72 to 40.52 mN/m, a high reactivity in the culture medium at pH 7, a high osmotolerance up to 150 g/L of salt, and a critical micellar concentration of 21 mg/L.


Assuntos
Pseudomonas aeruginosa , Esgotos , Tensoativos , Ecossistema , Hidrocarbonetos
8.
Bioprocess Biosyst Eng ; 42(7): 1205-1213, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30949844

RESUMO

In bubble column bioreactors, the hydrodynamic behavior like mixing time, bubble size and morphology of filamentous fungi are influenced by the construction of spargers. Sparger pore size is an important factor influencing formation of bubbles. In this study for the first time, a 5-L bubble column bioreactor with different porous spargers was used to investigate the effect of mean air bubble diameter (at 0.36, 0.18 and 0.09 cm) on fungal growth, broth viscosity, fungal pellet morphology and lovastatin production by the filamentous fungus Aspergillus terreus. All cultivations were carried out at air flow rate equal to 0.5 Lair L-1 min-1. The viscosity of the broth was influenced by both biomass concentration and size of the fungal pellets. The highest values of viscosity were observed at bubbles of 0.09 cm diameter after 192 h of cultivation. The largest fluffy pellets and the highest yield of lovastatin (443 mg/L) were obtained at air bubbles diameter of 0.18 cm. Lovastatin yield on biomass growth in this condition was, respectively, 1.7-fold and 3.5-fold higher than in the cultivations performed with air bubbles of 0.36 and 0.09 cm diameters. These laboratory scale experiment indicates that air bubble diameter has the impact on lovastatin production and A. terreus culture conditions.


Assuntos
Aspergillus/crescimento & desenvolvimento , Biomassa , Reatores Biológicos , Lovastatina/biossíntese , Ar , Cinética , Porosidade
9.
Environ Monit Assess ; 189(11): 583, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29071452

RESUMO

The heavy metal (Pb, Cd, Cr, and Ni) content of a fish species consumed by the Sistan population and its associated health risk factors were investigated. The mean concentrations of Pb, Cd, and Cr were slightly higher than the standard levels. The Ni content of fish was below the maximum guideline proposed by the US Food and Drug Administration (USFDA). The average estimated weekly intake was significantly below the provisional tolerable intake based on the FAO and WHO standards for all studied metals. The target hazard quotients (THQ) of all metals were below 1, showing an absence of health hazard for the population of Sistan. The combined target hazard quotient for the considered metals was 26.94 × 10-3. The cancer risk factor for Pb (1.57 × 10-7) was below the acceptable lifetime carcinogenic risk (10-5). The results of this study reveal an almost safe level of Pb, Cd, Cr, and Ni contents in the fish consumed by the Sistan population. Graphical abstract ᅟ.


Assuntos
Exposição Dietética/estatística & dados numéricos , Monitoramento Ambiental , Contaminação de Alimentos/estatística & dados numéricos , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Peixes , Contaminação de Alimentos/análise , Humanos , Irã (Geográfico) , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise
10.
J Environ Manage ; 165: 96-105, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26413803

RESUMO

This study aims to investigate the effectiveness of the electro-Fenton process on the removal of a second generation of fluoroquinolone, enoxacin. The electrochemical reactor involved a carbon-felt cathode and a platinum anode. The influence of some experimental parameters, namely the initial enoxacin concentration, the applied current intensity and the Fe(II) amount, was examined. The degradation of the target molecule was accompanied by an increase of the biodegradability, assessed from the BOD5 on COD ratio, which increased from 0 before treatment until 0.5 after 180 min of electrolysis at 50 mg L(-1) initial enoxacin concentration, 0.2 mmol L(-1) Fe(II) concentration and 300 mA applied current intensity. TOC and COD time-courses were also evaluated during electrolysis and reached maximum residual yields of 54% and 43% after 120 min of treatment, respectively. Moreover, a simultaneous generation of inorganic ions (fluorides, ammonium and nitrates) were observed and 3 short chain carboxylic acids (formic, acetic and oxalic acids) were identified and monitored during 180 min of electrolysis. By-products were identified according to UPLC-MS/MS results and a degradation pathway was proposed.


Assuntos
Antibacterianos/química , Enoxacino/química , Poluentes Químicos da Água/química , Ácido Acético/química , Antibacterianos/metabolismo , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Carbono/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Eletrólise , Enoxacino/metabolismo , Fluoretos/química , Ferro/química , Nitratos , Platina , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/metabolismo
11.
Environ Technol ; 36(13-16): 1837-46, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25650749

RESUMO

The purpose of this study was first to examine the electrochemical oxidation of two antibiotics, tetracycline (TC) and tylosin (Tylo), considered separately or in mixture, on a glassy carbon electrode in aqueous solutions; and then to assess the relevance of such electrochemical process as a pre-treatment prior to a biological treatment (activated sludge) for the removal of these antibiotics. The influence of the working potential and the initial concentration of TC and Tylo on the electrochemical pre-treatment process was also investigated. It was noticed that antibiotics degradation was favoured at high potential (2.4 V/ saturated calomel electrode (SCE)), achieving total degradation after 50 min for TC and 40 min for Tylo for 50 mg L(-1) initial concentration, with a higher mineralization efficiency in the case of TC. The biological oxygen demand in 5 days (BOD5)/Chemical oxygen demand (COD) ratio increased substantially, from 0.033 to 0.39 and from 0.038 to 0.50 for TC and Tylo, respectively. Regarding the mixture (TC and Tylo), the mineralization yield increased from 10.6% to 30.0% within 60 min of reaction time when the potential increased from 1.5 to 2.4 V/SCE and the BOD5/COD ratio increased substantially from 0.010 initially to 0.29 after 6 h of electrochemical pre-treatment. A biological treatment was, therefore, performed aerobically during 30 days, leading to an overall decrease of 72% of the dissolved organic carbon by means of the combined process.


Assuntos
Eletrólise/instrumentação , Esgotos/química , Tetraciclina/isolamento & purificação , Tilosina/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Carbono , Misturas Complexas/química , Misturas Complexas/isolamento & purificação , Misturas Complexas/efeitos da radiação , Eletroquímica/instrumentação , Eletrodos , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Vidro , Esgotos/análise , Tetraciclina/química , Tetraciclina/efeitos da radiação , Tilosina/química , Tilosina/efeitos da radiação , Água/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/efeitos da radiação , Purificação da Água/métodos
12.
Environ Technol ; 36(1-4): 450-4, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25187471

RESUMO

A solid/liquid system involving activated sludge immobilized in an agar medium and a non-aqueous phase liquid containing the target pollutant has been considered to treat a model hydrophobic volatile organic compound, toluene. The positive impact of the use of a multiphase bioreactor is that the organic phase constitutes a pollutant reservoir and also helps to overcome possible pollutant toxicity. In addition and to overcome the drawbacks of the use of a solid organic phase (high pressure drop and low mass transfer) instead of a liquid organic phase, the considered solid phase was the aqueous. Consequently, silicone oil (polydimethylsiloxane) which showed its relevance for implementation in multiphase bioreactors was used. Promising results were observed from the analysis of toluene in the gaseous phase; for an initial amount of 2 g L(-1) related to the organic phase, a v/v ratio of 0.5 of the organic phase to the aqueous agar phase, total toluene consumption was observed in about 9 days, leading to a global biodegradation rate of approximately 3.1 mg L(-1) h(-1), namely in the range of values previously observed in liquid/liquid systems.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Esgotos/química , Esgotos/microbiologia , Óleos de Silicone/química , Tolueno/química , Tolueno/isolamento & purificação , Poluentes Atmosféricos/química , Biodegradação Ambiental , Recuperação e Remediação Ambiental/métodos , Transição de Fase
13.
Environ Technol ; 36(1-4): 1-10, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25409577

RESUMO

A combined process coupling photocatalysis and a biological treatment was investigated for the removal of Bezacryl yellow (BZY), an industrial-use textile dye. Photocatalytic degradation experiments of BZY were carried out in two stirred reactors, operating in batch mode with internal or external irradiation. Two photocatalysts (TiO2P25 and TiO2PC500) were tested and the dye degradation was studied for different initial pollutant concentrations (10-117 mg L(-1)). A comparative study showed that the photocatalytic degradation led to the highest degradation and mineralization yields in a stirred reactor with internal irradiation in the presence of the P25 catalyst. Regardless of the photocatalyst, discoloration yields up to 99% were obtained for 10 and 20 mg L(-1) dye concentrations in the reactor with internal irradiation. Moreover, the first-order kinetic and Langmuir-Hinshelwood models were examined by using the nonlinear method for different initial concentrations and showed that the two models lead to completely different predicted kinetics suggesting that they were completely different.According to the BOD5/ Chemical oxygen demand (COD) ratio, the non-treated solution (20 mg L(-1) of BZY) was estimated as non-biodegradable. After photocatalytic pretreatment of bezacryl solution containing 20 mg/L of initial dye, the biodegradability test showed a BOD5/COD ratio of 0.5, which is above the limit of biodegradability (0.4). These results were promising regarding the feasibility of combining photocatalysis and biological mineralization for the removal of BZY.


Assuntos
Corantes/isolamento & purificação , Fotoquímica/instrumentação , Titânio/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Catálise , Corantes/química , Corantes/efeitos da radiação , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Estudos de Viabilidade , Luz , Modelos Químicos , Fotoquímica/métodos , Indústria Têxtil , Titânio/efeitos da radiação , Poluentes Químicos da Água/efeitos da radiação , Purificação da Água/métodos
14.
Environ Technol ; 35(5-8): 735-40, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24645454

RESUMO

A two-phase partitioning bioreactor was considered to remove toluene contained in a biodegradable organic phase by activated sludge (AS). The selected solvent was hexadecane. In a first step, the biodegradation of toluene dissolved in hexadecane by AS was examined. In a second step, acclimation of the AS was carried out in order to improve the biodegradation rate. Acclimation improved toluene removal, since biodegradation yield increased from 72% to more than 91%. A total consumption was observed after only 4 days culture with acclimated AS, since the rest of the toluene corresponded to gas leak; while in the case of non-acclimated sludge, losses cannot account for all non-degraded toluene. Regarding hexadecane, acclimation also improved its degradation, from 43% to 79% after 6 days culture for non-acclimated and acclimated AS, respectively.


Assuntos
Biodegradação Ambiental , Reatores Biológicos , Esgotos , Tolueno/química , Alcanos/química , Biomassa , Carbono/química , Gases , Solventes/química , Temperatura , Fatores de Tempo
15.
Environ Technol ; 35(21-24): 3082-91, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25244136

RESUMO

Carbamazepine (CBZ) is a recalcitrant xenobiotic pharmaceutical pollutant highly stable in soil and wastewater during treatment. The biodegradation of CBZ using streptomycetes has been few studied up to now. Sixteen newly filamentous bacteria belong to genus Streptomyces spp. isolated from different Romanian soil samples and three strains from a collection of microorganisms (MIUG) were morphologically characterized, tested based on their resistance against CBZ toxicity and then selected as agents for bioremediation. Five Streptomyces spp. strains coded MIUG 4.88, MIUG 4.89, SNA, LP1 and LP2 showed CBZ tolerance at all of the tested concentrations, i.e. 0.05, 0.2, 1, 5 and 8 mg L⁻¹. Two of these (MIUG 4.89 and SNA strains) were selected based on their resistance to target compound and were then assessed for CBZ biodegradation. The strain Streptomyces MIUG 4.89 showed an interesting efficiency for CBZ removal, with a yield of 35% when it was cultivated in submerged conditions on a minimal medium supplemented with 5 g L⁻¹ glucose. This ability was linked to extracellular laccase production. These results are promising for the use of these filamentous bacteria as bioremediation agents.


Assuntos
Anticonvulsivantes/metabolismo , Carbamazepina/metabolismo , Streptomyces/metabolismo , Biodegradação Ambiental , Biomassa , Lacase/metabolismo , Microbiologia do Solo , Streptomyces/crescimento & desenvolvimento , Streptomyces/isolamento & purificação
16.
Viruses ; 16(2)2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38399946

RESUMO

Enteroviruses (EVs) represent a major cause of viral meningitis, being responsible for nearly 1 billion infections each year worldwide. Several techniques were developed to obtain better diagnostic results of EV infections. Herein, we evaluated the efficiency of EV detection through isolation on both Rhabdomyosarcoma (RD) and Vero cell line cultures, conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Thus, 50 cerebrospinal fluid (CSF) samples belonging to patients suspected to have viral meningitis in northern Algeria were collected, anonymously numbered from 1 to 50 and subjected to the above-mentioned techniques for EV detection. Using real-time RT-PCR, 34 CSF samples were revealed to be positive for viral origin of meningitis (68%). Thirteen of them were positive when the conventional RT-PCR was used (26%), and only three samples gave positive results when the cell culture technique was used (6%). Surprisingly, two cell culture-positive CSF samples, namely, 31 and 39, were negative using RT-PCR directly on the original samples. However, they turned to be positive when amplification was carried out on their corresponding cell culture supernatant. The cell-cultured viral isolates were then identified by sequencing their viral genome's VP1 regions. All of them were revealed to belong to the echovirus 27 strain. This investigation demonstrates that RT-PCR techniques are often more sensitive, accurate and much faster, providing reliable results within a clinically acceptable timeframe. However, viral isolation on cell cultures remains crucial to obtain enough viral load for serological tests or even to avoid the rare, but existing, false negative PCR.


Assuntos
Infecções por Enterovirus , Enterovirus , Meningite Viral , Animais , Chlorocebus aethiops , Humanos , RNA Viral/análise , Enterovirus/genética , Meningite Viral/diagnóstico , Células Vero , Antígenos Virais , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
Biotechnol J ; 19(1): e2300096, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38050663

RESUMO

Microalgae have been widely recognized as a promising feedstock for sustainable biofuels production to tackle global warming and pollution issues related to fossil fuels uses. This study identified and analyzed indigenous microalgae strains for biodiesel production, specifically Chlorella vulgaris and Coelastrella thermophila var. globulina, from two distinct locations in Algeria. Molecular identification confirmed their identity, and the microalgae exhibited notable growth characteristics. Local Chlorella vulgaris and Coelastrella thermophila var. globulina showed good growth and high biomass yield, compared to Chlorella vulgaris CCAP211/11B reaching a weight of 1.48 g L-1 , 1.95 g L-1 , and 2.10 g L-1 , respectively. Lipids content of local Chlorella vulgaris, Coelastrella thermophila var. globulina, and Chlorella vulgaris CCAP211/11B, were found to be 31.39 ± 3.3%, 17 ± 2.26%, and 19 ± 0.64%, respectively. Chlorella vulgaris stood out as a candidate for biodiesel production due to its equilibrium between SFA and PUFA (43.24% and 45.27%). FAs are predominated by SFA and MUFA for Coelastrella thermophila var. globulina with value of 81.49% (SFA+MUFA). Predicted biodiesel qualities comply with ASTM6751 and EN14214 standards. Studied microalgae have therefore a promising potential for biodiesel production. However, optimising cultivation conditions is necessary to enhance biomass and lipids yield at a large scale.


Assuntos
Chlorella vulgaris , Microalgas , Ácidos Graxos , Biocombustíveis , Biomassa
18.
J Environ Manage ; 128: 981-7, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23895910

RESUMO

This research focuses on the identification and quantification of odorous components in rendering plant emissions by GC/MS and other analytical methods, as well as the description of phenomena occurring in biofilter in order to improve the removal efficiency of industrial biofilters. Among the 36 compounds quantified in the process air stream, methanethiol, isopentanal and hydrogen sulfide, presented the major odorous contributions according to their high concentrations, generally higher than 10 mg m(-3), and their low odorous detection thresholds. The elimination of such component mixtures by biofiltration (Peat packing material, EBRT: 113 s) was investigated and revealed that more than 83% of hydrogen sulfide and isopentanal were removed by biofilter. Nevertheless, the incomplete degradation of such easily degradable pollutants suggested inappropriate conditions as lack of nutrients and acidic pH. These inadequate conditions could explain the lack of performance, especially observed on methanethiol (53% of RE) and the production of oxygenated and sulfur by-products by the biofilter itself.


Assuntos
Poluentes Atmosféricos/análise , Filtração/métodos , Indústria de Processamento de Alimentos , Odorantes/análise , Aldeídos/análise , Filtração/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Sulfeto de Hidrogênio/análise , Concentração de Íons de Hidrogênio , Solo , Compostos de Sulfidrila/análise
19.
Environ Technol ; 34(5-8): 853-60, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23837336

RESUMO

Olive mill wastewater (OMW) is a substantial pollutant not only because of its high organic matter content and recalcitrant compounds such as polyphenols, but also due to its high chemical oxygen demand and biological oxygen demand. Its degradation by means of hydroxyl radicals generated from microwave application in the presence of hydrogen peroxide and Cu(II) has been investigated. The optimal experimental conditions were found to be a microwave intensity of 680 W, the presence of Cu(II) and relatively concentrated hydrogen peroxide (12 mol L(-1)). In these conditions, discolouration of OMW reached 98.0 +/- 0.2% and phenolic compounds decreased to 81.8 +/- 0.2% of their initial concentration after 12 min microwave time. Fourier transform infrared analysis confirmed that microwave degradation of phenols by means of the Fenton-like system Cu(II)/H2O2 could be an efficient solution for the treatment of olive mill wastewater.


Assuntos
Cobre/química , Peróxido de Hidrogênio/química , Resíduos Industriais/prevenção & controle , Ferro/química , Olea/química , Águas Residuárias/química , Purificação da Água/métodos , Indústria de Processamento de Alimentos , Micro-Ondas , Águas Residuárias/análise
20.
J Environ Sci (China) ; 25(9): 1906-12, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-24520735

RESUMO

A fungal consortium including Aspergillus niger, Mucor hiemalis and Galactomyces geotrichum was tested for the treatment of dairy wastewater. The bio-augmentation method was tested at lab-scale (4 L), at pilot scale (110 L) and at an industrial scale in Wastewater Treatment Plants (WWTP). The positive impact of fungal addition was confirmed when fungi was beforehand accelerated by pre-culture on whey (5 g/L lactose) or on the dairy effluent. Indeed, chemical oxygen demand (COD) removal yields increased from 55% to 75% for model medium, diluted milk. While after inoculation of an industrial biological tank from a dairy factory with the fungal consortium accelerated by pre-cultivation in a 1000 L pilot plant, the outlet COD values decreased from values above the standard one (100 mg/L) to values in the range of 50-70 mg/L. In addition, there was a clear impact of fungal addition on the 'hard' or non-biodegradable COD owing to the significant reduction of the increase of the COD on BOD5 ratio between the inlet and the outlet of the biological tank of WWTP. It was in the range of 451%-1111% before adding fungal consortium, and in the range of 257%-153% after bio-augmentation with fungi. An inoculated bioreactor with fungal consortium was developed at lab-scale and demonstrated successfully at pilot scale in


Assuntos
Biodegradação Ambiental , Reatores Biológicos , Indústria de Laticínios , Fungos/metabolismo , Águas Residuárias , Projetos Piloto
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