Chemical Industry Effluent Research Articles

Identification of Pops Organic Compounds in Sediment in the Cisangkuy Watershed Using GC-MS Analysis Method

The Cisangkuy Watershed is a tributary of the Upper Citarum River located in the Bandung Basin, West Java. Based one previous research, one organic pollution in the Cisangkuy Watershed is the presence of POPs (Persistent Organic Pollutants) compounds. POPs are organic compounds that can last a very long time in the environment (persistent) and have toxic properties for organisms. This study aims to identify and analyse the organic content of POPs and sediments in the Cisangkuy Watershed, as well as to analyse the source of pollutants and categorise them based on the Stockholm Convention on Persistent Organic Pollutants. Identification of POPs compounds using gas chromatography-mass spectrometry (GC-MS) technique. Sediment sampling was conducted by grab sampling that involved 20 sampling points from upstream to downstream of the Cisangkuy Watershed (CS-1 to CS-20). Samples were collected from 9 sub-districts. The research location shows that the land activities at the sampling point include asphalt hot mix, pharmaceutical, textile, and manufacturing industries. The results showed the presence of 1,2-Benzenedicarboxylic acid, mono (2-ethylhexyl) ester, 4,8,12-Tetradecatrienenitrile, 5,9,13-trimethyl-, and 2-Hexyl-1-octanol compounds at sampling points from upstream to downstream. These compounds were derived from chemical industry effluents, fossil fuel combustion, and agricultural activities. The compounds are classified as ‘industrial waste’ and ‘industrial waste with antibiotic properties’ by the Stockholm Convention on Organic Waste Management.

Isotherm and kinetic investigations of sawdust-based biochar modified by ammonia to remove methylene blue from water

Chemical industry effluent may pose significant environmental risks to both human health and the economy if it is not properly managed. As a result, scientists and decision-makers are paying increasing attention to developing a sustainable, low-cost wastewater treatment technique. This work aims to investigate the adsorption of Methylene Blue (MB) dye present in water using biochar derived from sawdust modified by boiling in an ammonia solution (SDBA). The properties of SDBA were characterized by BET, SEM, XRD, BJH, FT-IR, DTA, EDX and TGA analyses. The presence of –OH and –NH groups in SDBA was confirmed by FTIR, which proved that the NH4OH treatment of biochar successfully added nitrogen groups on its surface. The influence of pH (2 to 12), MB dye initial concentration (20 to 120 mg/L), adsorbent dosage (0.5 to 4.0 g/L) and contact time (0 to 180 min) on the adsorption process has been investigated. The adsorption of MB dye is more favorable at basic pH, with optimum adsorption at pH 8. Using a starting concentration of 20 mg/L of MB dye and a 4.0 g/L SDBA dose, the maximum percent clearance of MB dye was 99.94%. Experimental results were fitted to the Freundlich (FIM), Tempkin (TIM) and Langmuir (LIM) isotherm models (IMs). The FIM fitted the equilibrium data well, with a 643.74 mg/g Qm. Various error function models were used to test the data obtained from IMs. According to Error Function results, experimental data showed that it fits better for LIM and FIM. Kinetic studies indicated that the MB dye adsorption procedure followed pseudo-second-order (PSOM) kinetics based on film diffusion (FDM), pseudo-first-order (PFOM) and intra-particle diffusion models (IPDM). MB dye sorption on the SDBA involved electrostatic interaction, surface participation, hydrogen bond and π–π interactions. The adsorption mechanism of MB dye by SDBA was proposed as physical adsorption via the electrostatic attraction process. SDBA is an effective adsorbent in removing MB dye from water. Six adsorption–desorption cycles of the MB dye were run through the regeneration of SDBA with only a minimal amount of adsorption capacity loss, demonstrating the reusability of manufactured SDBA.

Persistence of Heavy Metals in River Sirsa Around Industrial Hub Baddi, India.

The Indian riverine system has become dumping site for toxic industrial pollutants. For assessing the flow of pollutants at various trophic levels, it is primarily important to do elemental profiling first so as to detect their load in Sirsa tributary of river Sutlej flowing through foothills of Shivalik in Himachal Pradesh, around the industrial hub Baddi, Solan. The study area includes three observation sites (S1, S2, and S3) on river Sirsa and drainage system of Baddi industrial units; the Effluent Nallah as demarcated in figure1. Heavy metal concentrations in water samples were detected using inductively coupled plasma mass spectroscopy of elements (Ti, V, Cr, Co, Ni, As, Li, Cd, Cs, Pt, Pb, Hg) as these were found to be very common in effluents of chemical, cement, textile dyeing, electronics and pharmaceutical industries. Statistical analysis showed that the concentrations (ppb) of elements found to be within permissible limits of WHO at sites under study for seven metals (Hg, Li, Ti, V, Co, Cs, Pt) but it was higher for five toxic heavy metals (Cr, Ni, Pb, As, Cd) at S2 only, streamlined in order Cr >Ni > Pb> As >Cd >Hg >Li >Ti >V >Co > Cs > Pt. It may be due to improper installation of common effluent treatment plant (CETP) on the bank of river Sirsa or due to leakage by tanker carrying waste water from various industrial set ups as these units were not directly linked to CETP. These sites were committed to act as ultimate gutter to receive all types of industrial pollutants as part of mismanagement. The load of Arsenic and Lead is increasing in lotic region and its impact on aquatic ecosystem at trophic level can be explored to combat toxicant pollution.

Adsorption of Cr(VI) by Mesoporous Pomegranate Peel Biowaste from Synthetic Wastewater under Dynamic Mode

This study aims to eliminate hexavalent chromium Cr(VI) ions from water using pomegranate peel (PGP) powder. Dynamic measurements are carried out to examine the influence of the operating factors on the adsorption efficiency and kinetics. The analyzed PGP is found to be amorphous with relatively high stability, contains hydroxyl and carboxyl functional groups, a pH of zero charge of 3.9, and a specific surface-area of 40.38 m2/g. Adsorption tests indicate that PGP exhibits excellent removal effectiveness for Cr(VI) reaching 50.32 mg/g while the adsorption process obeys the Freundlich model. The thermodynamic study favors the exothermic physical adsorption process. The influence of operating parameters like the flow rate (1 to 3 mL/min), bed height (25 to 75 mm), concentration (10 to 30 mg/L), and temperature (298 to 318 K) on the adsorption process are investigated in column mode. To assess the performance characteristics of the column adsorption data, a non-linear regression has been used to fit and analyze four different kinetic and theoretical models, namely, Bohart-Adams, Thomas model, Clark, and Dose response. The obtained experimental results were found to obey the Dose Response model with a coefficient of regression R2 greater than 0.977. This study proved the excellent efficiency in the treatment of chemical industry effluents by using cost-effect abundant biowaste sorbent. This research demonstrated great efficacy in the treatment of chemical industrial effluents by using an abundant, cost-effective biowaste sorbent, thereby achieving the UN SDGs (UN Sustainable Development Goals) primary objective.

Synthesis of zeolite-A from bagasse ash and removal of heavy metals from industrial effluents

Zeolite-A was indirectly synthesised from bagasse ash from the sugar industry using a hydrothermal conversion method. Active silicon dioxide (SiO2) and aluminium oxide (Al2O3) were obtained from the bagasse ash and aluminium sulfate, respectively. The synthesis involves the dissolution of amorphous aluminosilicate releasing [SiO2(OH)2]−2 and Al(OH)−4, the formation of sodium aluminosilicate gel and the crystallisation of zeolite. Results showed that amorphous silica obtained from ash dissolved completely during the first hour of the crystallisation stage. With the increase in crystallisation time up to 4 h, a slight change in the composition of zeolite crystals was observed, due to the dissolution of zeolite-A. The synthesised zeolite showed an excellent adsorption capacity for heavy metal cations from aqueous solutions, especially for Pb++ (187.25 mg/g), followed by Cu++ (63.22 mg/g). This observation indicates that the zeolite-A synthesised from bagasse ash can be used as a low-cost and relatively effective adsorbent for the remediation of heavy metals from the effluents of chemical industries before being released to the environment.

Extraction of nanostructured sodium nitrate from industrial effluent and their thermal properties.

This study describes a process of extraction of high purity sodium nitrate from corrosive chemical industry effluents. Here, we have designed a process to convert highly corrosive effluents of ceramic industries having pH ~13.1 into sodium nitrate nanoparticles. The extraction of sodium nitrate has been carried out via neutralization of industrial effluent by nitric acid. We have also studied the effect of low boiling point co-solvent during recrystallization of sodium nitrate. TEM studies of sodium nitrate extracted from the filtrate in the absence of co-solvent show the formation of nanoparticle of ~70nm. Further, a drastic decrease in particle size to 10nm has been observed when co-solvents (methanol, ethanol, and acetone) were used in combination with filtrate during the recrystallization process of sodium nitrate. Thermal properties of sodium nitrate extracted from filtrate have been investigated. Our result indicates that the nanoparticles extracted from filtrate having very high heat storage density (453J/g) without hampering the melting point and boiling point of the materials. PRACTITIONER POINTS: The new chemical process has been developed to treat the industrial effluent Extraction of nanostructured sodium nitrate has been carried from industrial effluent The particle size of sodium nitrate drastically influenced by the used co-solvent for recrystallization The highest heat storage density is 453J/g, which was obtained from the recrystallization of the filtrate.

Biosorption of Methylene Blue Dye from Aqueous Solutions

Synthetic dyes, like methylene blue, in effluents of chemical industries, are reported to be toxic with alleged carcinogenic and genotoxic consequences. Biosorption is considered as a low-cost alternative to the costly removal processes. Agricultural wastes and plant biomass and are contemplated to be low-cost candidates because they can be used without or with a minimum of processing. This work was intended to test the possibility and comparative study of different low-cost natural adsorbents [Coconut husk (H), Groundnut shell (G), Cow Dung (C) and moss (M)] for the sequestration of methylene blue dye from aqueous solution. A batch process was done to study the effects of different parameters such as contact time, pH, adsorbent dosage and initial dye concentration. Adsorption equilibrium data were represented using Langmuir, Freundlich and Temkin isotherm models. 75 % of dye removal was observed with moss, hence proves to be an effective, low-cost adsorbent.

Kinetic and Isotherm Study of 2,4,6-Trichlorophenol’s Fast Adsorption from Aqueous Solutions by Synthesized Magnetite-Bentonite Nanocomposite

Organic pollutants in water have been the main contaminations of concern for man. 2,4,6-Trichlorophenol (TCP), is a toxic carcinogen phenolic derivative which exists in effluents of chemical industries and the removal of this pollutant is critical. As the removal of TCP from industrial effluents is important, various techniques have been applied such as adsorption, chemical oxidation, chemical coagulation, and anaerobic biodegradation. In adsorption technique, nanobentonite is considered as a suitable adsorbent due to the low cost, small size of particles, large surface area, naturally available, and intense adsorption capacity. To separate adsorbent particles easily through an external magnetic field, magnetic nanomaterials, such as Fe3O4, can be fixed on nanobentonite. In this research, magnetized bentonite nanocomposite was synthesized for fast adsorption of TCP from aqueous solutions. The adsorbent was characterized by a Vibrating-Sample magnetometer (VSM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and Zetasizer Nanoparticle analyzer and the effect of adsorbent dose; pH and contact time parameters on the adsorption process of TCP were evaluated. Moreover, the isotherms and adsorption kinetics were studied. The pH 5 was considered as the optimal pH. The results of kinetic experiments showed that by increasing the contact time, the adsorption efficiency was increased and the equilibrium contact time was found to be about 60 minutes. In optimal pH and equilibrium time (60 min) conditions with the adsorbent dose of 1 g/L, the percentage of adsorption by magnetized nanobentonite was achieved 96.777% while unmodified bentonite adsorbed 68.25% of TCP in equilibrium time of 3 h. The experimental data of adsorption indicated more conformity with the pseudo-second-order and Langmuir isotherm models. As a deduction, nanobentonite with high adsorption capacity was prepared from bentonite mines of Iran and magnetized by Fe3O4 leading to easy and fast separation of nanocomposite TCP from the solution.

New process for conversion of hazardous industrial effluent of ceramic industry into nanostructured sodium carbonate and their application in textile industry

Increase in industrialization as a tool to become global leader has led to an exponential rise in environmental pollution. The present study describes a process developed to extract nanocrystalline sodium carbonate from chemical industry effluents, which contributes to wealth creation from hazardous waste. Sodium carbonate is a high demand product because of its applications in detergents, dyeing, glass, and paper manufacturing. In the present work, we have extracted nanostructured sodium carbonate using industrial waste (alkaline solution of silicates, obtained from ceramic industry) and carbon dioxide (a major component of flue gas effluent from power plants). Here we have collected waste from ceramic industries, which is highly corrosive (pH 13–14) and disposal of such waste is dangerous to the environment and needs to be taken special care. Pure carbon dioxide has been purged in collected industrial waste to get nanoparticles and flakes structure of sodium carbonate at room temperature. The use of the nanostructured sodium carbonate in the dyeing of textiles was encouraging. Significantly, higher dyeing efficacy was observed compared to the fabric dyed in the absence of sodium carbonate (Na2CO3). The nanocrystalline particles show much better color strength than bulk sodium carbonate when K/S value was compared. Na2CO3 with the minimum particle size (26 nm) results in the maximum color strength (K/S = 14.49).

Development of Aerobic Granular Sludge for Chemical Industries Wastewater Treatment

Background: The world’s chemical industries are confronted with formidable environmental regulatory challenges in treating their wastewaters. Aerobic granulation is increasingly drawing interest of researchers engaging work in the area of biological wastewater treatment. Objectives: The objective is to develop a new cost-effective technique for treatment of chemical industry effluents. The possibility and effectiveness of this new enhanced biological treatment system were determined through mean diameter, relative hydrophobicity, sphericity, and sludge volume index (SVI5) of aerobic microbial aggregates. Scanning electron microscopy (SEM) analysis was also used to characterize the granules. Methods: The granules were cultivated in a single sequencing batch reactor (SBR) system fed with synthetic ethylene glycol (MEG) wastewater. The characteristics of the aerobic granular sludge were monitored during the study period. Results: Aerobic granules with dense and strong microbial structure as well as excellent settling ability were cultivated. Developed granules had an average size of 8.21 ± 2 mm. The process of granulation resulted in an increased biomass concentration from about 2500 to 4750 mg/L. The microbial granular sludge was able to remove 97% of the influent COD at organic loading rate (OLR) of 2.0 kg COD/m3.day, at the end of the study. Conclusions: The findings of the present study revealed that aerobic granular sludge could be successfully developed in a SBR and is capable in treating the simulated chemical industries wastewater.

Rhizofiltration of a Bordeaux mixture effluent in pilot-scale constructed wetland using Arundo donax L. coupled with potential Cu-ecocatalyst production

Rinsing tanks of crop sprayers produce significant volumes of Cu-rich Bordeaux mixture effluents (BME) that can be treated by rhizofiltration in constructed wetlands (CWs). A pilot-scale CW (6×600L) was developed to jointly rhizofiltrate such BME, produce Cu-rich root mat for ecocatalysis and provide usable shoot biomass with low Cu concentration. Three CW units were unplanted control (Ctrl) while three others were planted with Arundo donax L. (Ad) in floating racks. The rhizofiltration was carried out during 30days in the early growing season. Total Cu concentration in the BME was 4.4mgCuL−1. Copper removal peaked within the 48 first hours after Bordeaux mixture addition in the Ad and Ctrl units (i.e. 92 and 81% respectively). The BME Cu concentration met the requirement for indirect discharge of chemical industry effluents (i.e. 0.5mgCuL−1) at T48h (0.4±0.2) and T21days (0.4±0.1) for the Ad and Ctrl units, respectively. At day 30, in the Ad units, Cu concentration remaining in the water and distributed between A. donax roots, shoots was respectively 3.5, 33 and 0.5% of the initial Cu input. In the Ctrl units, Cu remaining in water was low (7%) and Cu removal (93%) could be partly explained by its immobilization in the Cu-rich biofilm (i.e. 207210±18516mgCukg−1) coating the vat wall. Foliar chlorophyll (i.e. a, b and total) and carotenoid contents decreased at day 30 but root and shoot dry weight (DW) yields increased by 23% and 47% per Ad unit, respectively. The shoot Cu concentration remained in the common range (i.e. 3–20mgCukg−1) while the root Cu concentration reached 623±140mgkg−1 allowing 786mg Cu removal by the root mat. Higher Cu concentration in BME or subsequent repetitions of treatment cycle must be tested to achieve at least 1000mgCukg−1 DW in roots (threshold value for Cu-ecocatalyst) whereas the biofilm role must deserve more attention.

Treatment of a chemical industry effluent by nanofiltration and reverse osmosis

Treatment of a chemical industry effluent by nanofiltration and reverse osmosis

Correction: Self-Organising Maps and Correlation Analysis as a Tool to Explore Patterns in Excitation-Emission Matrix Data Sets and to Discriminate Dissolved Organic Matter Fluorescence Components

Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

페놀분해세균 Rhodococcus pyridinovorans P21의 분리 및 페놀분해 특성

페놀과 각종 난분해성 화합물이 함유된 폐수를 미생물학적으로 처리하기 위하여 폭넓은 연구가 진행되고 있으나 이들 균주들은 200 ppm 이상의 고농도 페놀이 존재할 경우, 기질저해 현상에 따른 생육이 일어나지 않는 단점이 있다. 본 연구에서는 유류로 오염된 토양에서 고농도 페놀을 분해할 수 있는 P21 균주를 분리하였으며, 표현형 및 계통분류에 근거하여 동정한 결과, Rhodococcus pyridinovorans로 동정되었다. 본 균주에 의한 페놀분해 최적조건은 0.09% <TEX>$KNO_3$</TEX>, 0.1% <TEX>$K_2HPO_4$</TEX>, 0.3% <TEX>$NaH_2PO_4$</TEX>, 0.015% <TEX>$MgSO_4{\cdot}7H_2O$</TEX>, 0.001% <TEX>$FeSO_4{\cdot}7H_2O$</TEX>, 초기 pH 9 및 <TEX>$20-30^{\circ}C$</TEX>이었으며, 이 조건에서 1000 ppm의 페놀을 2일 만에 완전히 분해하였다. 1,500 ppm의 페놀은 3일 만에 완전히 분해할 수 있었으나 그 이상의 페놀은 분해할 수 없었다. 또한 본 균주는 toluene, xylene 및 hexane과 같은 독성 화합물을 이용하여 생육할 수 있었으며, chloroform에서는 생육할 수 없었다. The effluents of chemical and petroleum industries often contain non-biodegradable aromatic compounds, with phenol being one of the major organic pollutants present among a wide variety of highly toxic organic chemicals. Phenol is toxic upon ingestion, contact, or inhalation, and it is lethal to fish even at concentrations as low as 0.005 ppm. Phenol biodegradation has been studied in detail using bacterial strains. However, these microorganisms suffer from substrate inhibition at high concentrations of phenol, whereby growth is inhibited. A phenol-degrading bacterium, P21, was isolated from oil-contaminated soil. The phenotypic characteristics and a phylogenetic analysis indicated the close relationship of strain P21 to Rhodococcus pyridinovorans. Phenol biodegradation by strain P21 was studied under shaking condition. The optimal conditions for phenol biodegradation by strain P21 were 0.09% <TEX>$KNO_3$</TEX>, 0.1% <TEX>$K_2HPO_4$</TEX>, 0.3% <TEX>$NaH_2PO_4$</TEX>, 0.015% <TEX>$MgSO_4{\cdot}7H_2O$</TEX>, 0.001% <TEX>$FeSO_4{\cdot}7H_2O$</TEX>, initial pH 9, and <TEX>$20-30^{\circ}C$</TEX>, respectively. When 1,000 ppm of phenol was added to the optimal medium, the strain P21 completely degraded it within two days. Rhodococcus pyridinovorans P21 could grow in up to 1,500 ppm of phenol as the sole carbon source in a batch culture, but it could not grow in a medium containing above 2,000 ppm. Moreover, strain P21 could utilize toxic compounds, such as toluene, xylene, and hexane, as a sole carbon source. However, no growth was detected on chloroform.

Self-organising maps and correlation analysis as a tool to explore patterns in excitation-emission matrix data sets and to discriminate dissolved organic matter fluorescence components.

Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

Effects of chemical industry effluents on haematological parameters in mice

The present study was conductedto evaluate the effect of chemical industry effluents on hematological parameters in mice. Two-week-old 128 mice were randomly divided into four groups of 32in each viz. control (group-I), R2B vaccine + effluent treated (group-2), effluent treated (group-3) and R2B vaccinated (group-4). The vaccine used was R2B strains of Raniket Disease given to group-2 and 4 @ 0.1 ml by intraperitoneal route. The hematological parametersviz. hemoglobin, packed cell volume, total erythrocyte count and differential leucocyte count were performed at fortnight interval upto 120 days of experimentation. Cell mediated immune response was measured by Lymphocyte Stimulation Test (LST). It was observed that hemoglobin, packed cell volume, total erythrocyte count, total leucocyte count and differential leucocyte count as well as lymphocyte Stimulation Index decreased significantly in effluent treated group. Significant decrease in these parameters led to anaemia and suppression of cell mediated immune response in chemical industry effluent treated micein comparison to controls.

Electrochemical degradation of specialty chemical industry effluent

Conventional wastewater treatment techniques are inefficient to manage large quantities of refractory organics discharged by specialty chemical industries. It is aimed in the present investigation to compare overall performance of the basic electrochemical reactor configurations such as batch, batch recirculation and continuous recycle reactors, in removing the organic part of wastewater from a medium-scale, specialty chemical industry. The effects of current density, supporting electrolyte concentration, electrolysis duration and fluid flow rate on the pollutant removal and energy consumption performances were critically evaluated. Continuous recycle reactor is found to be the better configuration, because of its flexibility of operation. Circulation flow rate and withdrawal flow rate enable control on transfer coefficients and treatment duration respectively. The ability of artificial neural network (ANN) in predicting the performance of the batch electrochemical treatment has also been demonstrated.

Combination of in vitro bioassays for the determination of cytotoxic and genotoxic potential of wastewater, surface water and drinking water samples

In this study we evaluated genotoxicity and cytotoxicity of native samples of wastewaters (15 samples), surface waters (28 samples) and potable waters (8 samples) with the SOS/ umuC assay with Salmonella typhimurium TA1535/pSK1002 and MTT assay with human hepatoma HepG2 cells. The genotoxicity of selected samples was confirmed with the comet assay with HepG2 cells. In the SOS/ umuC assay 13 out of the 51 samples were genotoxic: two effluent samples from chemical industry; one sample of wastewater treatment plant effluent; two hospital wastewater samples; three river water samples and four lake water samples. Six samples were cytotoxic for HepG2 cells: both effluent samples of chemical industry, two wastewater treatment plant effluent samples, and two river water samples, however, only the chemical industry effluent samples were genotoxic and cytotoxic, indicating that different contaminants are responsible for genotoxic and toxic effects. Comparing genotoxicity of river and lake water samples with the chemical analytical data of the presence of the residues of pharmaceutical and personal care products (non-steroidal anti-inflammatory drugs, UV filters and disinfectants) in these samples, indicated that the presence of UV filters might be linked to the genotoxicity of these samples. The results showed that the application of the bacterial SOS/ umuC assay and mammalian cell assays (MTT and comet assay) with HepG2 cells was suitably sensitive combination of assays to monitor genotoxicity and cytotoxicity of native samples of wastewaters and surface waters. With this study we also confirmed that the toxicity/genotoxicity bioassays should be an integral tool in the evaluation of toxicity of complex wastewaters before the release into environment, as well as for the monitoring of surface water quality, providing data useful in risk assessment.

Enhanced electron transfer by bovine serum albumin covalently attached to glassy carbon electrode and its application to determination of hydroquinone

Bovine serum albumin (BSA) was covalently attached to glassy carbon electrode (GCE) surface by the electrochemical method. An enhancement for the redox of hydroquinone (HQ) on BSA/GCE was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy measurement. The electron transfer rate constant (k s) on the BSA/GCE electrode is almost three orders of magnitude higher than that on bare GCE. The enhancing effect can be attributed to the electrostatic force between the positively charged HQ and negatively charged BSA. It is found that the enhanced redox process of HQ can be used to determine HQ sensitively. The oxidation current can reach 95% of its steady-state value within 30 s. The linear range for HQ determination is from 2.5 × 10−8 M to 1.325 × 10−6 M with a detection limit of 8.6 × 10−9 M at a signal-to-noise ratio of 3. The study may provide a simple, rapid and sensitive method for determination of HQ which is present in the natural environment and in chemical industry effluent.

Catalytic Destruction of 4‐Chlorophenol in Water

Abstract4‐Chlorophenol (4‐CP) is a toxic, hazardous and persistent pollutant entering water mainly via the effluents of chemical industries. Catalytic wet oxidation has been the favored green chemistry path to convert this chlorinated organic to benign products. Wet oxidation was attempted in this work with MCM‐41 based catalysts impregnated with Fe(III), Co(II), and Ni(II). The catalysts were characterized with X‐ray diffraction, scanning electron microscopy, FTIR, cation exchange capacity, and atomic adsorption spectrophotometric measurements. 4‐CP oxidation was carried out in water, with and without hydrogen peroxide. The efficiency of the catalysts was tested with respect to reaction time, pH, mole ratio of the reactant and the oxidant, catalyst load, feed concentration, and temperature. The typical reaction conditions of temperature of 353 K, time 300 min, catalyst load 2 g/L, 4‐CP concentration 10–3 M could achieve 50.2, 55.0 and 58.2% oxidation in the presence of H2O2 and 48.5, 58.6 and 60.2% oxidation in the absence of H2O2 with Fe(III)‐, Co(II)‐, and Ni(II)‐MCM‐41, respectively. The reactions followed pseudo‐first‐order kinetics with respect to 4‐CP and the kinetic constant was between 1.4·10–3 and 3.5·10–3 Lg–1min–1. A mechanism for the oxidation of 4‐CP is suggested on the basis of product analysis.