Synthetic Industrial Effluent Research Articles

Treatment of Synthetic Industrial Effluent Aiming at the Removal of Glyphosate by Means of Advanced Oxidation

Objective: The purpose of this study was to assess the efficiency of an advanced oxidative process gradually applying different oxidative agents, i. e. UV, TiO2 and O3, to evaluate the removal efficiency of a commercial composition of glyphosate from an aqueous matrix. Theoretical framework: In Brazil, approximately 150 million liters of glyphosate are consumed per year, representing 30% of the total pesticides used, which can contaminate surface water due to aerial or terrestrial spraying, erosion and runoff, improper disposal of commercial packaging and cleaning of contaminated spray tanks. Advanced oxidative processes have emerged as an alternative to the degradation of glyphosate since they have high efficiency in reducing organic contaminants to an acceptable limit with a low operating cost. Method: Experimental consisted of a benchtop-scale system, composed of a batch reactor with a 25W UV lamp inside and a feeding pump in a recirculation reservoir. It was responsible for performing the removal of glyphosate by means of an advanced oxidative process after receiving TiO2 and O3 application. Results and conclusion: The photolysis process obtained an efficiency of 24.69%, the photocatalytic oxidation process with TiO2 obtained 37.78%, and the photocatalytic ozonation with TiO2 obtained 45.46% efficiency in 60 minutes of reaction. The possible formation of byproducts after one hour of reaction due to the increase in concentration was also observed, since it was not possible to distinguish glyphosate from other compounds in the analysis method applied. Implications of the research: As demonstrated by the results of the experimental assays, the advanced oxidative technique proved to be very efficient to make the removal of a commercial composition of glyphosate from an aqueous matrix. Originality/value: It has been shown that it is possible to remove glyphosate in an efficient way, using a highly efficient fast technique.

Microwave synthesized erbium vanadate nano-photocatalyst: Application for enhanced degradation of contaminated water

The subject of treatment of real or synthetic industrial effluents and photocatalysts has concerned a lot of consideration from scientists. Among the diverse metal oxide photocatalytic materials, the narrow bandgap compounds are of superior significance owing to appropriate efficiency in the optical application. In this work, we produced pristine ErVO4 through the microwave-assisted synthesis method. Diverse solvents and different power intensities have been employed in this preparation for size controlling and shape engineering, such as Ethylene glycol (EG), Propylene glycol (PG), and Polyethylene glycol (PEG-400) and power of 900, 750 and 600 W. XRD, FT-IR, and EDS analysis have been utilized to demonstrate the phase purity, and FE-SEM and TEM were employed to discover the shape of resultant ErVO4. The several attributes of the samples, such as the surface area, magnetic and optical features, were inquired by BET, VSM and DRS techniques, correspondingly. Microwave power of 900 W and Ethylene glycol solvent was selected as an optimal condition owing to the creation of uniform nanosized particles. So nanostructured ErVO4 was operated as a catalyst for the decolorization of colored pollutants (Erythrosine (ER), Methyl Orange (MO), and methylene blue (MB)). According to the discoveries, the MB with higher photocatalytic efficiency was compared in different dye concentrations and catalyst loading experiments to attain ideal performance.

Efficiency evaluation of orange and banana peels for dye removal from synthetic industrial effluent

With this increase in the urbanization and industrialization of the textile industry and paint industry, there is a vast utilization of the dye in the daily use. This had led to the increase in the availability of the dye waste among the effluent water from such industry. The present work focuses on evaluation of the effectiveness of using the naturally available orange and banana peels as the biosorbent for the removal of the different dyes available in the waste effluents from most of the industries. The use of such bio-based materials used to decrease the environmental impact of the harmful adsorbents. The parameters such as different initial concentration of dyes, adsorbent dosage, pH of the solution and the impeller speed were evaluated. The outcome of the experiments focused to show that the adsorption efficiency of banana peels and orange peels amplified with an augmentation of the adsorbent dosage. Approximately 76 % of the removal of dye was achieved with a blend of the adsorbent dosage of 1 g/50 mL of dye solution, 200 rpm and a pH of 8. The equilibrium experimental data supported the validation of the Langmuir model of adsorption suggesting the monolayer adsorption. The maximum adsorption capacity for the exclusion of Malachite green utilizing orange and banana peel is obtained as 42.55 and 40.98 mg g−1 respectively.

Polyethylene glycol functionalized reduced graphene oxide coupled with zinc oxide composite adsorbent for removal of phenolic wastewater

The development of agricultural activities and industrialization recently has various adverse impacts on living organisms. The ever-increasing problem of organic pollution has been an environmental concern to the community. Among these, phenolic pollutants like 2,4–dichlorophenol (2,4–DCP), phenol, 2–chlorophenol (2–CP), and bisphenol–A (BPA) are priority toxic pollutants that are continuously released into environment from many industries. In this work, a biocompatible zinc oxide incorporated polyethylene glycol functionalized reduced graphene oxide composite (RGO-PEG-ZnO) was synthesized and explored for the adsorptive removal of toxic phenolic pollutants from water. The optimized adsorption parameters were solution pH 7, adsorption time 60 min, temperature 25 °C, and dosage 0.25 g/L. The isotherms were well fitted by the Langmuir model for BPA and phenol, whereas for 2–CP, and 2,4–DCP, Freundlich was the best-fitted model, and the maximum uptake of BPA, phenol, 2–CP, and 2,4–DCP were 485.756, 511.248, 531.804, 570.641 mg/g, respectively. The kinetic data for all the phenolic pollutants follow the pseudo-second-order model. The thermodynamic analysis shows that Gibb's free energy (ΔGo) values for all the pollutants were negative, confirming that the process was spontaneous. The positive values of change in enthalpy (ΔHo) 28.261, 37.205, 46.182, and 61.682 kJ/mol for BPA, phenol, 2–CP, and 2,4–DCP, respectively, confirm that the above adsorption process was endothermic. The composite can be used for up to five cycles with a small reduction in the removal percentage. Adsorption performance of the synthesized composite for synthetic industrial effluents shows that up to 86.54% removal occurred in 45 min adsorption time. Based on the remarkably rapid adsorption and high adsorption capacity, RGO-PEG-ZnO composite can be considered an efficient adsorbent for treating phenolic pollutants from wastewater.

Synthesis of novel epichlorohydrin cross-linked β-cyclodextrin functionalized with reduced graphene oxide composite adsorbent for treatment of phenolic wastewater.

A novel composite consisting reduced graphene oxide-functionalized beta-cyclodextrin epichlorohydrin polymer (RGO-βCD-ECH) was synthesized for the treatment of phenolic wastewater. Batch study of phenolic pollutants (2,4-dichlorophenol, 2-chlorophenol, and phenol) was analyzed using the synthesized composite as an adsorbent from an aqueous solution. The optimized parameters were temperature 25°C, adsorption time 60min, solution pH 7, and dosage 0.25g/L. The isotherm data were more suitably fitted by the Langmuir isotherm model. The maximum uptake for 2,4-dichlorophenol, phenol, and 2-chlorophenol was 702.853, 659.475, and 674.155mg/g, respectively, at 25 ± 1°C. The kinetic data for all the phenolic pollutants follow the pseudo-second-order model, and the rate was controlled by film diffusion. Thermodynamic data revealed that the process of removing phenolic pollutants is spontaneous and endothermic. The composite can be used up to five cycles with a small reduction in the removal. Adsorption performance of the synthesized composite for synthetic industrial effluents shows that up to 78% removal occurred in 60min adsorption time. Based on the remarkably rapid adsorption and high adsorption capacity, the synthesized composite can be considered an efficient adsorbent for treating phenolic pollutants from wastewater.

TREATMENT OF A TEXTILE WASTEWATER USING AN ELECTROCOAGULATION REACTOR POWERED BY PHOTOVOLTAIC SOLAR ENERGY

The textil industry uses a variety of dyes in the stage of coloring. The liquid effluent resulting at the end of the process has high turbidity and a large chemical oxygen demand. If these byproducts are dumped into natural water bodies, even in small quantities, they may produce damage to the aquatic environment and to human health. Electrocoagulation is becoming an efficient technique for the removal of pollutants from industrial effluents, it is easy to operate, and produces little sludge at the end of the treatment. In the present study, the use of an electrocoagulation reactor with aluminum electrodes proved efficient for turbidity removal from synthetic industrial effluents. The use of a solar plate of photovoltaic electricity for the functioning of the reactor was evaluated. Ideal time of treatment was 20 minutes. The use of a conventional energy source removed 63% of the turbidity. Using the voltaic solar energy source, a removal of 72% of turbidity was attained. We conclude that it is possible to use the alternative solar energy source in order to minimize costs resulting from electrical energy consumption, and, at the same time, to obtain the best results in the removal of pollutants.

Hazardous wastewater treatment by low‐cost sorbent with in situ regeneration using hybrid solar energy‐electrochemical system

Hazardous industrial wastes negatively impact the environment by creating issues for aquatic as well as human's life. This study investigates the treatment of hazardous industrial wastewater using cost-effective graphite adsorbent along with electrochemical regeneration integrated with renewable solar energy. The synthetic industrial effluent containing crystal violet dye was treated using an adsorbent (Nyex™ 1000) having a surface area of 1.0m2 g-1 . The efficiency of removing solute was found to be more than 90%. The adsorbent regeneration efficiency was achieved at 99.5% by passing a charge of 100Cg-1 at current density of 10mAcm-2 for 1h. Solar energy was integrated with electrochemical reactor for the regeneration of adsorbent to make the system cost-effective and self-sustainable. PRACTITIONER POINTS: Industrial hazardous wastewater treatment with a cost-effective graphite integrated adsorbent. Development of renewable solar energy-integrated with electrochemical system for regeneration. Regeneration efficiency of adsorbent Nyex™ 1000 was achieved around 99.5% with integrated system. Sustainable system was introduced to incorporate with renewable energy for waste water treatment.

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Removal of total dissolved solids from wastewater using a revolving algal biofilm reactor.

Total dissolved solids (TDS) comprising inorganic salts and organic matters are pollutants of concern to aquatic systems and water for human use. This work aimed to investigate the use of revolving algal biofilm (RAB) reactors as a sustainable and environmental friendly method to remove TDS from industrial effluents and municipal wastewaters. The wastewaters contained chloride, sodium, potassium, calcium, magnesium, and sulfate as the major components. The RAB reactors fed with synthetic industrial effluent with high TDS level demonstrated the best algal growth, with the highest TDS removal efficiency (27%) and removal rate (2,783mg/L-day and 19,530mg/m2 -day). A suspended algal culture system only removed 3% TDS from the same wastewater. The TDS removal by the RAB reactors was considered due to several mechanisms such as absorption by the algae cells, adsorption by extracellular polymeric substance of the biofilm, and/or precipitation. Collectively, this research shows that the RAB reactors can serve as an efficient system in wastewater remediation for TDS removal. PRACTITIONER POINTS: Total dissolved solids (TDS) in wastewater are pollutants of concern. The RAB reactors can remove TDS from various types of wastewater. The RAB reactors removed TDS by adsorbing ions elements such as Cl, Na, K, Ca, Mg, and S. The algal biomass absorbs ions through extracellular polymeric substance.

Double-Silicate Derived Hybrid Foams for High-Capacity Adsorption of Textile Dye Effluent: Statistical Optimization and Adsorption Studies.

In this work, a lightweight inorganic-organic hybrid foam adsorbent is processed out of economically cheap "double-silicate" precursors employing natural bentonite and water glass through a facile cross-linking and polymerization technique. Poly(vinyl alcohol) was used to provide structural strength to the three-dimensional framework. The foam adsorbent possessed an apparent density of 0.083 g cm-3, indicating its internetworks and exposed surface area for the uptake of dyes. The foam was systematically studied for the treatment of textile dye effluent. Multivariate optimization process was carried out using response surface methodology. The Box-Behnken model was used for the design of experiments and to study the interplay between the variables. Batch adsorption and continuous column adsorption studies were carried out at respective levels of initial concentration (200-1000 μM), adsorbent dose (1-10 g L-1), and contact time (0-120 min). The results revealed that the hybrid silicate foam exhibits adsorption capacity as high as 99.9, 98.9, and 98.2% for 200, 600, and 1000 μM concentrations of methylene blue in 120 min, respectively, and 100% adsorption for 200, 600, and 1000 μM concentrations of crystal violet in 120 min for 10 g L-1 of adsorbent. Adsorption equilibrium data fitted well to Langmuir isotherm, and the kinetics followed second-order kinetic model. Synthetic industrial effluent with 1000 μM dye concentration was also prepared and studied with continuous column for determining the working capacity of the adsorbent, and the results are presented. The silicate hybrid foam is a cheap adsorbent that does not produce any secondary waste and can be repeatedly used making it attractive for dye industries.

Adsorption of cadmium, nickel and lead ions: equilibrium, kinetic and selectivity studies on modified clinoptilolites from the USA and RSA.

The performance of modified clinoptilolites (zeolites) from two different sources (South Africa and the USA) for the adsorption of Ni2+, Cd2+ and Pb2+ from synthetic industrial effluent contaminated with metal concentration levels at 50, 150 and 500ppm was evaluated. The selectivity of the clinoptilolite for the adsorption of Ni2+, Cd2+ and Pb2+ was investigated with mixed feed solutions containing all three ions in equal concentrations and single-component concentrations containing only one of the ions. The homoionic forms of the clinoptilolite were made of Na+, K+ and Ca2+. Batch experiments were then conducted to measure the uptake of metals by the zeolites. The zeolites were characterised using SEM, XRD and BET. The South African clinoptilolite showed a higher surface area and pore volume (17.52m2/g and 0.047cm3/g respectively) than the USA zeolite (12.26m2/g and 0.028cm3/g respectively) for the Na+ homoionic form. According to the equilibrium studies, the selectivity sequence was found to be Pb2+ > Cd2+ > Ni2+, with good fits being obtained using Langmuir and Freundlich adsorption isotherms for low metal concentrations. Examples of equilibrium adsorption capacities for RSA and USA clinoptilolite modified with Na+ for Pb were 26.94mg/g and 27.06mg/g when RSA-Na+ and USA-Na+ were used respectively. The adsorption was found to depend on the homoionic form of the zeolite and to a lesser extent the source of the zeolite. The selectivity of a particular zeolite for a particular heavy metal can be altered by the homoionic form of the zeolite. Overall, the adsorption capacity of the USA clinoptilolite was higher than the adsorption capacity of the SA clinoptilolite, revealing the potential of clinoptilolite in metal-polluted industrial effluent treatment.

Investigation on adsorption kinetics of heavy metals by rice husk

Removal of heavy metal ions and their derivative forms from the environment has become a priority to safeguard the quality of the ecosystem. In this context, the present study is based on the removal of Cd(II), Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) from synthetic industrial effluents using heat-treated rice husk, which can be used to develop cost-effective and ecofriendly effluent treatment procedures. The characterisation experiments reveal that Si available in rice husk in high percentage and many chemical functional groups present on the surface are involved in the adsorption mechanism. Metal ions commonly present in effluents of metal finishing industries were specially considered for their removal. The optimum firing temperature of rice husk, determined using 10.0 mg L-1 solutions of each metal ion, was 100 oC. The effect of other experimental parameters, such as contact time and pH were also investigated using rice husk fired at the optimised temperature of 100 oC. Kinetics studies conducted for the interaction of the above metal ions and rice husk lead to the validity of pseudo second order kinetics with high regression coefficients. The initial rate of adsorption ( ho ) of metal ions varies in the order of Pb(II) > Zn(II) > Cd(II) > Cu(II) > Ni(II) > Cr(III). According to the diffusion models investigated, Weber and Morris intraparticle diffusion model supports the data for rate constant of particle diffusion, which varies in the same order as observed in initial adsorption rate measurements ( ho ).

Removal of Basic Blue 9 Dye by Hydrogen Peroxide Activated by Electrogenerated Fe<sup>2+</sup>/Fe<sup>3+</sup> and Simultaneous Production of Hydrogen

Electrochemical techniques were used to oxidize organic pollutants by Fenton process using a mix of H2O2 and ferrous ions at a parallel plate reactor. The first stage was to build a micro scale reactor comprising two compartments, cathode and anode, separated by a membrane (Nafion-117). Each compartment has inlets and outlets to allow the flow of fluids (10 Lmin-1). The function of the reactor is to oxidize organic pollutants as well as to produce H2. Hydrogen is electrogenerated in the catholyte by the reduction of protons on a carbon steel cathode in acidic medium (0.05 M H2SO4). At the same time, a mixture of Fe2+/Fe3+ ions is produced in the anolyte (0.05 M Na2SO4, pH ≈ 2) by means of the oxidation of a sacrificial electrode made of stainless steel mesh. Fe2+/Fe3+ ions interact with H2O2 to generate strong oxidants which are responsible for oxidizing the organic matter and removing color. A voltage of 1 V was applied between the electrodes and remained constant, while the current observed was approximately 0.06 A. Under these conditions, the activation rate with different H2O2 concentrations (15, 20, 25, 30, 35, 40, 45 and 50 mM) was evaluated. The maximum activation rate (1.3 mM·min-1) was obtained using 30 mM H2O2. Under these conditions, the oxidation of a synthetic industrial effluent (0.615 mM BB9) was performed and the following results were obtained: 95% of this concentration was removed in 5 minutes and 15 mL of H2 was electrogenerated in 30 minutes.

Electrochemical Determination of Cibacron Red FN-R at Glassy Carbon Electrode

The electrochemical oxidation of c ibacron red FN-R (CB) has been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) in phosphate buffer solutions of pH (2.54–11.79) used as supporting electrolytes. The voltammetric behaviour showed that the electro-oxidation process gave rise to a single peak at 0.692 V vs. Ag-AgCl using DPV in phosphate buffer solution at (pH 3.34). The oxidation process was shown to be irreversible and adsorption-controlled. An analytical method was developed for the determination of cibacron red FN-R in phosphate buffer solution at (pH 3.34) as supporting electrolyte. The anodic peak current varied linearly with cibacron red FN-R concentration in the range 2.0 ×10 �6 mol L -1 to 1.0 ×10 �5 mol L �1 of cibacron red FN-R with a limit of detection (LOD) of 4.49 ×10 �7 mol L �1 and limit of quantification (LOQ) of 1.49 ×10 -6 mol L �1 . Validation parameters, such as accuracy, precision and recovery were evaluated. The proposed method was successfully applied to the determination of cibacron red FN-R in synthetic industrial effluents and the analytical results compared well with those obtained by the spectrophotometric method .

Removal of chromium and nickel ions from aqueous solution by adsorption on modified coconut husk.

The study investigated the adsorption of Cr(VI) and Ni(II) on modified coconut husk (low cost adsorbent) for the remediation of Cr(VI) and Ni(II) from some synthetic industrial waste effluents. The coconut husk was modified by mixing with 0.1 M NaOH and HCl respectively. The effects of varying adsorbent loading, hydrogen ion concentration, contact time and temperature of adsorption were studied. Similar experiments were carried out using unmodified coconut husk, in order to compare the results obtained from the modification experiments. The result showed that the HCl modified adsorbent gave 96% ± 3.6 removal for Cr(VI) at a pH of 4.0 while about 99% ± 0.7 of Ni(II) was removed at a higher pH of 7.0. The unmodified adsorbent gave a 90% ± 8.8 adsorption for Cr(VI) and 97% ± 1.5 for Ni(II) respectively. However, the NaOH modified adsorbent gave the least adsorption of 40% ± 9.9 for Cr(VI) and 80% ± 6.1 for Ni(II). The equilibrium data for the adsorption of Cr(VI) and Ni(II) on coconut husk was tested using both the Freundlich and Langmuir adsorption isotherms. The Freundlich isotherm was found to be more suitable for Cr(VI) adsorption, while the Langmuir isotherm was observed to better for Ni adsorption on coconut husk. To evaluate the mechanism of adsorption, pseudo-first order and second order kinetic models were used. The adsorption mechanism was found fit the second order. The HCl modified adsorbent gave the best result for removal of Cr(VI) from synthetic industrial effluents.

Treatment of arsenic contaminated water in a laboratory scale up-flow bio-column reactor

The present paper describes the observations on the treatment of arsenic contaminated synthetic industrial effluent in a bio-column reactor. Ralstonia eutropha MTCC 2487 has been immobilized on the granular activated carbon (GAC) bed in the column reactor. The synthetic water sample containing As(T) (As(III):As(V) = 1:1), Fe, Mn, Cu and Zn at the initial concentrations of 25, 10, 2, 5, 10 ppm, respectively, was used. Concentrations of all the elements have been found to be reduced below their permissible limits in the treated water. The significant effect of empty bed contact time (EBCT) and bed height on the arsenic removal was observed in the initial stage. However, after some time of operation (approximately 3–4 days) no such effect was observed. Removal of As(III) and As(V) was almost similar after ∼2 days of operation. However, at the initial stage As(V) removal was slightly more than that of As(III). In absence of washing, after ∼4–5 days of operation, the bio-column reactor was observed to act as a GAC column reactor based on physico-chemical adsorption. Like arsenic, the percent removals of Fe, Mn, Cu and Zn also attained minimum after ∼1 day and increased significantly to the optimum value within 3–4 days of operation. Dissolved oxygen (DO) has been found to decrease along with the increasing bed height from the bottom. The pH of the solution in the reactor has increased slightly and oxidation–reduction potential (ORP) has decreased with the time of operation.

Effects of competitive ions, humic acid, and pH on removal of ammonium and phosphorous from the synthetic industrial effluent by ion exchange resins

The removal of the ammonium and phosphorous from the synthetic industrial effluent by the ion exchange resins was studied in this paper, aiming at the determination of the effects of competitive ions, humic acid, pH and resin amount. The kinetic experiments show that the equilibrium time for the removal of both contaminants in the absence and presence of the competing matters was 4 h. Na + and K + significantly reduced the ammonium removal percentage, while the existence of Mg 2+, Ca 2+ and humic acid also had a negative influence. Adsorption of ammonium ions in both absence and presence of Na + and K + observed the linear isotherm, however, it did not follow commonly used isotherms in the presence of Na +, K +, Mg 2+, Ca 2+ and humic acid. The phosphorous removal decreased in the presence of the competitive matters, such as Cl −, CO 3 2−, SO 4 2− and humic acid. Higher pH can cause higher phosphorous removal percentage. A decrease in the solution pH was observed in the phosphorous removal experiments, possibly due to the ion exchange and the adsorption of OH −. Uptake of humic acid by the resins was observed. Finally, a series of fixed-bed experiments were performed, showing that the performance was dependent on the empty bed contact time (EBCT). Higher EBCT would cause higher bed volumes of both treated ammonium and phosphorous.

Separation of oil from water by dissolved air flotation

Abstract Synthetic industrial effluent was prepared by stabilising low concentrations of oil (Catenex 11, Shell, UK) in aqueous dispersion with a non-ionic surfactant (Span 20) and dissolved air flotation (DAF) was used to clarify this wastewater. Operating parameters including saturator pressure, recycle ratio, and air to oil ratio, were investigated to find conditions that would enhance the efficiency of the DAF separation. The zeta potential of the emulsion droplets and flocculated oil droplets was determined and aluminium sulphate and four different cationic polyelectrolytes were used to destabilise the system. Measurements indicated that a saturator efficiency of about 90% was achieved and it was found that increasing the working pressure of saturator had less effect in the separation of oil droplets than increasing recycle ratio. Optimum conditions for separation are obtained with an air to oil ratio of 0.0075 corresponding to a recycle ratio of 10%. The zeta potential measurements indicate that oil droplets are negatively charged between pH 5 and 10. In addition the zeta potential measurements of flocculated oil droplets were found to depend strongly on the concentration of the polyelectrolyte. Although an inversion of the oil droplets charge was observed even at very low polyelectrolytes concentration. The polyelectrolytes were ineffective in enhancing the separation. This effect can be related to the structure of the polyelectrolytes and to the adsorption mechanism. In contrast, when aluminium sulphate was used it was found that it is important to decrease the magnitude of zeta potential in order to decrease electrostatic repulsion so that the emulsion was destabilised prior to flotation. Under these conditions DAF yields near complete oil separation even at moderate working pressure and recycle ratio when the oil droplets are destabilised.