Electroplating Industry Effluent Research Articles

Microalgae Potentials for Phycoremediation with Paint Effluent of Electroplating Industry

Water pollution is a one of the major environmental issue that the world is facing nowadays. The untreated effluent as well as the chemically treated effluent both results in pollutions. These toxic contaminants directly and indirectly affect the flora and fauna of the ecosystem. The solution for such a drastic environmental issue lies within the cells of one such cosmopolitan plant group namely “Algae”. These are certain algal species which have the inhibit capacity to utilize some of the most threatening environmental contaminants such as nitrogenous compounds, ammonia, phosphates and some of the metal ions so on. Hence, treating the effluent with algae would be an eco-friendly method to reduce pollution. Phycoremediation of effluent using algae is a novel green-technique when applied to aqueous pollution. The present investigation included the preliminary screening of microalgae potentials for their tolerance and growth in paint effluent from an electroplating industry which include the native microalgae isolated from the effluent treatment plant (ETP). The microalgae, such as Chlamydomonas pertusa, Dactylococcopsis raphioides and Chlorococcum humicolo were selected and employed in the treatment of electroplating paint effluent an individually and also as mixed algal group. The physico-chemical parameters were analyzed. The individual culture and the mixed algal culture both could effectively reduce TDS (Total Dissolved Solid), TSS (Total Suspended Solid), free ammonia, calcium, sodium, nitrate and phosphate. Chlorococcum humicolo had a significant remedial level of Turbidity (20.51%), Calcium (95.76%), Sodium (8.33%), Free ammonia (62.96%), Phosphate (71.29%) and Total Kjeldhal Nitrogen (48.23%) treated with paint effluent of electroplating industry among the microalgae. Thus, Chlorococcum humicolo could be selected for further field pilot scaling up study. Phycoremediation is a cost-effective, efficient and a sustainable technology for future clean earth.

Synthesis, characterization and application of novel green chelating PE-TH resin in the removal of toxic metals from industrial effluents

One of the world's most serious environmental issues is water contamination produced by toxic metal ions from industrial wastewater. Heavy metal contamination has posed a severe threat to human health and the environment due to its toxicity. To investigate this issue, water contaminated by industrial waste must be rectified with paramount importance. The necessity of generating innovative, environmentally safe remedies to ensure the security of human life and environment is recognized by green chemistry. The purpose of the present research is to synthesize the novel plant-based green chelating resin to trap toxic metal ions from industrial wastewater. The Psyllium Epichlorohydrin Tyrosin Hydroxamate (PE-TH) resin is prepared by crosslinking Psyllium with Epichlorochydrin and Tyrosine amino acid. The total ion exchange capacity (Q) obtained for PE-TH resin is 5.780meq/g. The adsorption coefficient ‘Kd' is obtained by employing the batch adsorption method. The PE-TH resin proved to be very efficient in removing predominantly Cu (II) and Ni (II) ions from the electroplating industry wastewater. The pH range of 7-7.5 produced significant elimination of Cu (II) and Ni (II). The PE-TH resin satisfactorily adsorbs Cu (II) and Ni (II) metal ions from electroplating industry effluents. The newly synthesized PE-TH resin is easy to prepare and is eco-friendly, cost-effective and biodegradable green chelating agent to remove toxic metals ions efficiently from industrial effluents.

Treatment of electroplating industry wastewater: a review on the various techniques.

Water pollution by recalcitrant compounds is an increasingly important problem due to the continuous introduction of new chemicals into the environment. Choosing appropriate measures and developing successful strategies for eliminating hazardous wastewater contaminants from industrial processes is currently a primary goal. Electroplating industry wastewater involves highly toxic cyanide (CN), heavy metal ions, oils and greases, organic solvents, and the complicated composition of effluents and may also contain biological oxygen demand (BOD), chemical oxygen demand (COD), SS, DS, TS, and turbidity. The availability of these metal ions in electroplating industry wastewater makes the water so toxic and corrosive. Because these heavy metals are harmful to living things, they must be removed to prevent them from being absorbed by plants, animals, and humans. As a result, exposure to electroplating wastewater can induce necrosis and nephritis in humans and lung cancer, digestive system cancer, anemia, hepatitis, and maxillary sinus cancer with prolonged exposure. For the safe discharge of electroplating industry effluents, appropriate wastewater treatment has to be provided. This article examines and assesses new approaches such as coagulation and flocculation, chemical precipitation, ion exchange, membrane filtration, adsorption, electrochemical treatment, and advanced oxidation process (AOP) for treating the electroplating industry wastewater. On the other hand, these physicochemical approaches have significant drawbacks, including a high initial investment and operating cost due to costly chemical reagents, the production of metal complexes sludge that needs additional treatment, and a long recovery process. At the same time, advanced techniques such as electrochemical treatment can remove various kinds of organic and inorganic contaminants such as BOD, COD, and heavy metals. The electrochemical treatment process has several advantages over traditional technologies, including complete removal of persistent organic pollutants, environmental friendliness, ease of integration with other conventional technologies, less sludge production, high separation, and shorter residence time. The effectiveness of the electrochemical treatment process depends on various parameters, including pH, electrode material, operation time, electrode gap, and current density. This review mainly emphasizes the removal of heavy metals and another pollutant such as CN from electroplating discharge. This paper will be helpful in the selection of efficient techniques for treatment based on the quantity and characteristics of the effluent produced.

Biosorption of Cu(II), Pb(II) from electroplating industry effluents by treated shrimp shell

The current investigation focuses on a systematic study of application of treated shrimp shell waste (TSSW) as a potential biosorbent in removal of Cu(II) and Pb(II) from hazardous industrial effluents. The surface characterization and morphological studies indicated that biosorption is owing to ion complexation and exchange, and chemical adsorption mechanism. The effects of pH (1–10), time dependency (1–60 min), initial concentration of Cu(II) and Pb(II) (20–100 mg L−1), TSSW loading (0.1–0.5 g) and temperature (303–333 K) on biosorption efficiency using TSSW were examined through experiments. The experimental discoveries indicated that maximum biosorption efficacies were 96.42% at pH 5, 40 min for Cu (II) and 89.77% at pH 6, 30 min for Pb(II), 20 mg L−1 concentration, 0.1 g loading and 303 K temperature. Langmuir, Freundlich, Temkin, and Dubinin - Radushkevich isotherm models were used to examine experimental findings and the Langmuir model was well fitted one. The maximum Cu(II), Pb(II) removal capacities by TSSW were 22.67, 15.32 mg g−1 according to Langmuir model. Pseudo second order model was excellent suited to kinetics which shows that chemisorption was involved for the transfer of Cu(II), Pb(II) to TSSW surface with three different intra particle diffusional stages. Hence, this study revealed that TSSW has a great potential to be an environment friendly and economic biosorbent for removal of Cu(II) and Pb(II) containing industrial effluent.

Biosorption efficiency of nickel by various endophytic bacterial strains for removal of nickel from electroplating industry effluents: an operational study.

Realising the hazardous effect of nickel on human health, microbes and plants are effectively used for bioremediation. The endophytic microorganisms have an important role in the phytoremediation of nickel using Vigna radiata. Therefore, in order to harness the potential of microbial strains, the present study was designed to examine the metal biosorption ability of endophytic bacterial strains isolated from plants growing in nickel-contaminated soil. A total of six endophytic nickel resistance bacteria were isolated from the plant Vigna radiata. The metal tolerant bacterial strains were identified following 16 S rRNA gene sequence analysis. Nickel biosorption estimation and plant growth-promoting (PGP) activities of isolated strains were performed and found high nickel biosorption efficiency of 91.3 ± 0.72% at 600 mg L-1 using Bacillus safensis an isolated endophytic strain from Vigna radiata. Furthermore, high indole acetic acid (IAA) and exopolysaccharide (EPS) production were obtained in all the strains as compared to without nickel-containing medium used as control. Moreover, the production of high EPS suggests improved biosorption ability of isolated endophytic strains. In addition, a kinetic study was also performed to evaluate different adsorptions isotherms and support the nickel biosorption ability of endophytic strains. The treatment of nickel electroplating industrial effluent was also demonstrated by isolated endophytic strains. Among six (6) strains, B. cereus showed maximum 57.2 ± 0.62% biosorption efficiency of nickel which resulted in the removal of 1003.50 ± 0.90 mg L-1 of nickel from the electroplating industry effluents containing initial 1791 ± 0.90 mg L-1 of nickel. All other strains were also capable of significant nickel biosorption from electroplating industry effluents as well. Thus, isolated endophytic nickel tolerant strains can be further used at large-scale biosorption of nickel from electroplating industry effluent.

Carbonized agrowastes uses for the removal of heavy metals Cr (VI), Ni (II), Cu (II) and Zn (II) from electroplating effluent at Agra, U.P. (India)

The physico-chemical tests were conducted using an electroplating industry effluent that contained 18.0, 18.9, 8.6 and 15.6 ppm of Cr(VI), Ni(II), Cu(II) and Zn(II) respectfully. The work aimed to evaluate the feasibility of using powdered pseudo activated carbon prepared from agro wastes for the removal of heavy metals from electroplating effluents. The ability of coconut coir carbon (CCC), sagaun sawdust carbon (SSC), wheat stem carbon (WSC) and rice husk carbon (RHC) to remove heavy metals from the effluent was studied. The sorption was in the order of Ni > Zn > Cu > Cr over a wide range of initial concentrations: 1-20 mg/l at sorbent dose 1 g/l. The sorption increased with increasing contact time but the equilibrium was attained in two hours for Cr, 3.0 h for Cu, 3.5 h for Zn and 4 h for Ni. The order of metal removal capacities for these chemical sorbents was: RHC > CCC > WSC > SSC. Electroplating effluent showed 4-10% lower removal as compared to synthetic standard solution under similar conditions.

Induction of non-protein thiols and phytochelatins by cadmium in Eichhornia crassipes

Impact of root Cd concentration on production of cysteine, non-protein thiols (NP-SH), glutathione (GSH), reduced glutathione (GSSG), and phytochelatins (PCs) in Eichhornia crassipes exposed to different dilutions of brass and electroplating industry effluent (25%, 50%, and 75%), and synthetic metal solutions of Cd alone (1, 2.5, and 3.5 ppm) and with Cr (1 ppm Cd + 1 ppm Cr, 2.5 ppm Cd + 3 ppm Cr, and 3.5 ppm Cd + 4 ppm Cr) was assessed in a 45 days study. Different treatments were used to understand and compare differential antioxidant defense response of plant under practical drainage (effluent) and experimental synthetic solutions. The production of NP-SH and cysteine was maximum under 2.5 ppm Cd + 3 ppm Cr treatments i.e., 1.78 µmol/g fw and 288 nmol/g fw, respectively. The content of GSH declined whereas that of GSSG increased progressively with exposure duration in all treatments. HPLC chromatograms revealed that the concentrations of PC2, PC3, and PC4 (248, 250, and 288 nmol-SH equiv.g−1 fw, respectively) were maximum under 1 ppm Cd, 1 ppm Cd + 1 ppm Cr, and 2.5 ppm Cd + 3 ppm Cr treatments, respectively. PC2, PC3, and PC4 concentrations increased with Cd accumulation in the range 812–1354 µg/g dry wt, 1354–2032 µg/g dry wt and 2032–3200 µg/g dry wt, respectively. Thus, the study establishes a direct proportionality relationship between concentration/length of phytochelatins and root Cd concentrations, upto threshold limits, in E. crassipes.

The Purification of Electroplating Industry Effluents with Agricultural Waste

The article suggests the usage of ash from sunflower husk combustion, which is constantly considered to be production waste, as a treating agent for electroplating industry wastewater purification. The chemical and mineral composition of ash waste has been researched by means of X-ray diffraction method with an X-ray fluorescent spectrometer. The structure of waste has been studied with a high-resolution scanning electron microscope. The ash contains calcium, magnesium and potassium oxides, so this waste can be used as a chemical treating agent in purifying water from heavy metals. The acid leaching of ash has been performed to determine the degree of its components transition. The trial purification of real electroplating wastes with the ash has been carried out. The purification efficiency for nickel and copper amounts to 62.0 and 48.0 % at the ash consumption 3.0 g/dm3.

Effects of effluent from electoplating industry on the immune response in the freshwater fish, Cyprinus carpio

The present study was designed to assess the effect of sublethal concentrations of electoplating industry effluent (EIE) on the non-specific and specific immune responses in the freshwater fish, Cyprinus carpio. Sublethal concentrations of electroplating industry effluent such as 0.004, 0.007, 0.010 and 0.013% were chosen based on the LC50 values. Experimental fish were exposed to these sublethal concentrations of EIE for 28 days. After 7, 14, 21 and 28 days of treatment, non-specific immune response by serum lysozyme activity, myeloperoxidase activity and antiprotease activity and specific immune response by antibody response to Aeromonas hydrophila using bacterial agglutination assay and ELISA were assessed. The results showed that chronic exposure of fish to 0.004, 0.007, 0.010 and 0.013% EIE, dose-dependently decreased the non-specific and specific immune responses on all the days tested compared to control fish whereas statistically significant suppressive effects were observed in fish exposed to 0.013% of EIE on all activities tested.

Process parametric study for COD removal of electroplating industry effluent.

This paper investigated the effects of parameters, like inoculum size (15, 10 and 5% of the working volume of the reactor), gas velocities (0.0027, 0.00342 and 0.0068m/s), bed heights (0.3, 0.6 and 0.9m), static bed heights (4.85 and 2.43cm), sizes of solid media particles (12, 4mm), and the height to diameter ratio (H/D: 0.25 and 0.5) onto COD reduction process for electroplating effluent (initial COD values: 1140ppm) using Pseudomonas aeruginosa and Pseudomonas putida. The authors derived simple mathematical correlations representing the entire COD reduction process. The correlation between the inoculum volume and gas velocities was in the form of an equation Y=ax2+bx+c, as deduced from nonlinear regressions. The correlations were validated, and percentage errors were found out to infer the effects of all parameters in the COD reduction process. The maximum COD reduction was achieved to 28.30ppm (97.52%), in a batch mode, at 10% inoculum size, 0.0027m/s low gas velocity and a static bed height of 2.43cm.

Impact of electroplating effluent on growth of Triticum aestivum and Hordeum vulgare

Abstract The present study was planned to determine the effects of electroplating industry effluent on germination and various growth parameters (shoot length, root length, numbers of nodes and internodes) of Triticum aestivum and Hordeum vulgare. Biochemical characteristics i.e. estimation of proline, protein and sugar content were also studied. Heavy metals form a major category of contaminants reported to be present in large quantities in wastewaters and are matter of concern due to their toxicity and non-biodegradable nature. Heavy metals released into the environment shows regular increasing trends which is a significant threat to the environment and public health. Results revealed that the application of effluent on the studied plants Triticum aestivum and Hordeum vulgare directly affects the growth parameters and the biochemical characteristics.

Removal of heavy metals from industrial effluent using Pinus roxburghii leaves as biosorbent: equilibrium modelling

In the present study, biosorption capability of pine (Pinus roxburghii) leaves for the removal Cr(6+), Cu(2+), Fe(2+) and Zn(2+) ions, present in brass and electroplating industry effluent, were investigated with respect to different adsorbent doses, contact time and pH. Heavy metals concentrations were estimated by atomic absorption spectrophotometry. Initial concentration of Cr(6+), Cu(2+), Fe(2+) and Zn(2+) ions in the effluent were found to be 2.741, 4.551, 8.820 and 5.529 mg/L respectively. Biosorption studies revealed that Cr(6+), Cu(2+), Fe(2+) and Zn(2+) showed maximum removal of 99.85, 94.54, 97.10 and 89% at pH 4, 4, 4 and 8, respectively, with 4 g pine leaves when shaken at 150 rpm for 60 min. The applicability of the three equilibrium isotherm models was investigated and the data obtained fitted the three investigated isothermal models in the order: Langmuir > Temkin > Freundlich for all the studied metal ions. The adsorption isotherm coefficients, Qmax, b, Kf, n, at, bt were also calculated. Very high regression correlation coefficients (R(2) > 0.9) were found for Cu(2+), Fe(2+) and Zn(2+); Cr(6+) (Temkin isotherm) when pH (2-8) was varied; Cr(6+), Cu(2+),Fe(2+) and Zn(2+) when contact time (15-60 min) was varied; Cu(2+) (Langmuir isotherm) Fe(2+) (Freundlich and Temkin isotherms) when adsorbent was varied from 2 to 5 g. Results also revealed that among all the studied ions Cr(6+) at varied pH and Fe(2+) at different adsorbent doses satisfy the Temkin and Freundlich isotherm models to describe the biosorption equilibrium by pine (Pinus roxburghii) adsorbent.

Removal of Chromium from Electroplating Industry Effluent Using Electrocoagulation

Experiments were performed in batch mode of operation using iron electrodes to remove chromium from effluent by electro- coagulation, and the effect of various operating parameters was investigated. The maximum hexavalent chromium removal efficiency of 100% from a synthetic solution containing hexavalent chromium was obtained for an electrolysis time of 15 min at the optimum current density of 50 mAcm −2 , interelectrode distance 0.5 cm, and solution pH of 4. The real electroplating industry effluent was characterized using the standard diphenylcarbazide (DPC) method. A 100% chromium removal efficiency was obtained for both trivalent and hexavalent chro- mium, for an electrolysis time of 45 min at 4 pH. It was found that Cr(VI) is initially reduced to Cr(III) in the acidic medium. An increase in the pH of the effluent was also noticed in the acidic medium due to the generation of hydroxyl ions. Experiments were performed for the removal of chromium using ferric chloride as the coagulant, and it was found that electrocoagulation is more efficient and relatively faster compared to chemical coagulation. DOI: 10.1061/(ASCE)HZ.2153-5515.0000170. © 2013 American Society of Civil Engineers. CE Database subject headings: Coagulation; Chromium; Iron compounds; Abatement and removal. Author keywords: Electrocoagulation; Electroplating effluent; Hexavalent chromium; Trivalent chromium; Iron.

Simultaneous bioaccumulation of multiple metals from electroplating effluent using Aspergillus lentulus

Toxic impacts of heavy metals in the environment have lead to intensive research on various methods of heavy metal remediation. However, in spite of abundant work on heavy metals removal from simple synthetic solutions, a very few studies demonstrate the potential of microbial strains for the treatment of industrial effluents containing mixtures of metals. In the present study, the efficiency of an environmental isolate (Aspergillus lentulusFJ172995), for simultaneous removal of chromium, copper and lead from a small-scale electroplating industry effluent was investigated. Initial studies with synthetic solutions infer that A. lentulus has a remarkable tolerance against Cr, Cu, Pb and Ni. During its growth, a significant bioaccumulation of individual metal was recorded. After 5 d of growth, the removal of metals from synthetic solutions followed the trend Pb2+ (100%) > Cr3+ (79%) > Cu2+ (78%), > Ni2+ (42%). When this strain was applied to the treatment of multiple metal containing electroplating effluent (after pH adjustment), the metal concentrations decreased by 71%, 56% and 100% for Cr, Cu and Pb, respectively within 11 d. Based on our results, we propose that the simultaneous removal of hazardous metals from industrial effluents can be accomplished using A. lentulus.

Removal of Copper-Cyanide Complexes from Electroplating Industry Effluents by Ion-Exchange Fiber

Removal of copper-cyanide complexes from electroplating industry effluent were studied by using an ion-exchange process. A kind of polypropylene strong alkaline anion exchange fiber was used to perform packed beds continuous experiments. The conditions of adsorption were wastewater pH value 9.0 and flow rate 90-120 BV•h-1 at room temperature. The packed beds were exhausted at 1300 bed volumes for copper-cyanide complexes The elution of copper-cyanide complexes from ion-exchange fiber was studied. The results showed that copper-cyanide complexes were easily eluted from ion exchange fiber using either 2.0 mol•L-1 NaNO3 or NaCl. With 1.0 mol•L-1 NaNO3 solution at 30 BV•h-1, the regenerating rate of copper-cyanide complexes was more than 95%.

Reduction of Cr (VI) in electroplating wastewater and investigation on the sorptive removal by WBAP

AbstractThe aim of the present investigation was to study the removal of total chromium from the electroplating industry effluent using Weathered Basalt Andesite Products (WBAP). The reduction of Cr (VI) to Cr (III) by hydrazinium sulfate (HS) was adopted. The sorbent WBAP before and after sorption, was characterized by FTIR, X‐ray diffraction, SEM, TEM, and TGA methods. The effects of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial metal ion concentration, and temperature on the removal of Cr (III) from aqueous solution was studied. Thermodynamic parameters (ΔH0, ΔS0, and ΔG0) for the sorption process were evaluated. Freundlich, Langmuir, and Dubinin‐Kaganer‐Radushkevich isotherm models were examined to describe the sorption isotherms. Analysis of sorption results obtained showed that the sorption pattern followed the Freundlich sorption isotherm. Langmuir maximum sorption capacity of WBAP for Cr (III) was found to be 12.07 mg/g. The process follows Pseudo second order rate and surface diffusion is identified as the predominating mechanism. The effluent having average discharge of total chromium 90 mg/L was successfully treated with the same sorbent with a removal of 85.65%. © 2010 American Institute of Chemical Engineers Environ Prog, 2011

Development of a biological system employing Aspergillus lentulus for Cr removal from a small‐scale electroplating industry effluent

AbstractIn spite of the abundant work on biological Cr removal from simple synthetic solutions, very few studies demonstrate the potential of the tested strain for treatment of potentially toxic and complex industrial effluents. In the present study, the efficiency of an environmental isolate, Aspergillus lentulus AML05, to remove Cr from a small‐scale electroplating industry effluent (pH 2.5, Cr (VI) 259 mg l−1 and total Cr 295 mg l−1), was investigated. To bring about Cr removal using growing biomass, dilution and nutrient supplementation of the effluent was tested. The removal of Cr (VI) after 9 days of treatment was 100% in the diluted effluent (1:1; effluent:growth media) and 99% in the undiluted nutrient supplemented effluent. About 73% of the total Cr was also removed. While using the non‐growing (pre‐cultivated) biomass, Cr (VI) removal within 2 h of contact was 75% (resting biomass) and 91% (autoclaved biomass). The maximum Cr (VI) removal was 90–92% after 24 h of treatment at various doses in the non‐growing mode. Comparison with earlier studies revealed that A. lentulus is a promising strain that can be efficiently utilized for Cr removal from industrial effluents. Overall, the study reveals that integrated system incorporating A. lentulus in both growing as well as non‐growing modes assumes significance in terms of an inbuilt assurance of the proper functioning of the biological system under any unforeseen fungal growth situation in the field. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

Characterization of Adsorptive Capacity and Investigation of Mechanism of Cu2+, Ni2+ and Zn2+ Adsorption on Mango Peel Waste from Constituted Metal Solution and Genuine Electroplating Effluent

The present study reports the potential of mango peel waste (MPW) as an adsorbent material to remove Cu2+, Ni2+, and Zn2+ from constituted metal solutions and genuine electroplating industry wastewater. Heavy metal ions were noted to be efficiently removed from the constituted solution with the selectivity order of Cu2+ > Ni2+ > Zn2+. The adsorption process was pH-dependent, while the maximum adsorption was observed to occur at pH 5 to 6. Adsorption was fast as the equilibrium was established within 60 min. Maximum adsorption of the heavy metal ions at equilibrium was 46.09, 39.75, and 28.21 mg g for Cu2+, Ni2+, and Zn2+, respectively. Adsorption data of all the three metals fit well the Langmuir adsorption isotherm model with 0.99 regression coefficient. Release of alkali and alkaline earth metal cations (Na+, K+, Ca2+, Mg2+) and protons H+ from MPW, during the uptake of Cu2+, Ni2+, and Zn2+, and EDX analysis of MPW, before and after the metal sorption process, revealed that ion exchange was the main mechanism of sorption. FTIR analysis showed that carboxyl and hydroxyl functional groups were involved in the sorption of Cu2+, Ni2+, and Zn2+. MPW was also shown to be highly effective in removing metal ions from the genuine electroplating industry effluent samples as it removed all the three metal ions to the permissible levels of discharge legislated by environment protection agencies. This study indicates that MPW has the potential to effectively remove metal ions from industrial effluents.

Preparation, characterization and performance of nanofiltration membranes for the treatment of electroplating industry effluent

Two new nanofiltration (NF) membranes were prepared by coating (cast and spray) of strong chelating agent diethylene triamine pentaacetic acid (DTPA), using polyether sulfone (PES) ultrafiltration (UF) membrane as substrate and their performance were studied to treat actual electroplating industry wastewater. The resulting membranes, observed to be nanofiltration membranes, were characterized with the help of scanning electron microscopy (SEM) and swelling behavior. The structure of sprayed membranes was observed to be more porous than that of cast membranes and hence, the sprayed membranes gave higher permeation rate than that of cast membranes. Effects of pressure, feed flow rate, feed pH, and concentration of DTPA on the rejection of zinc and iron were investigated. The rejection was higher for cast membrane when compared to spray membrane. The maximum observed rejection for cast and spray membranes was found to be 94% and 89% for zinc and 93% and 88% for iron, respectively. The rejection of SS and TDS was over 99.4%. From the experimental results it was evident that as pressure, and feed flow increased, the observed rejection of both the metal ions increased. Also, it was observed that the feed pH had great effect on permeate flux but marginal influence on observed rejection for both ions.

Removal of chromium from electroplating industry effluents by ion exchange resins

Effluent discharged from the chromium electroplating industry contains a large number of metals, including chromium, copper, nickel, zinc, manganese and lead. The ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species. The main objective of the present work is to evaluate the performance of commercial ion exchange resins for removing chromium trivalent from industrial effluents, and for this purpose two resins were tested: a chelating exchange resin (Diaion CR11) and a weak cationic resin (Amberlite IRC86). In order to evaluate the sorption capacity of the resins some equilibrium experiments were carried out, being the temperature and pH the main variables considered. The chromium solutions employed in the experiments were synthetic solutions and industrial effluents. In addition, a transient test was also performed as an attempt to understand the kinetic behaviour of the process.