Electroplating Waste Water Research Articles

Modular hydrogel selectively adsorbs phosphates and hexavalent chromium while enabling phosphate recovery

Electroplating wastewater containing high concentrations of phosphates and hexavalent chromium Cr(VI) poses serious environmental pollution. Moreover, phosphorus, as a non-renewable resource, necessitates its recovery to meet sustainable development goals. To address this issue, this study used sodium alginate as the scaffold module, synthesized lanthanum carbonate in situ within a chitosan module to serve as the phosphate adsorption module, and employed polyethyleneimine (PEI) modules to enhance the adsorption capacity for Cr(VI), successfully fabricating a modular hydrogel (LC-CSP). LC-CSP exhibits a complex porous structure and surface morphology, forming an ultra-low-density fiber network with good strength and elasticity, ensuring uniform distribution and exposure of active sites. Under optimal conditions for single-component adsorption, LC-CSP achieved adsorption capacities of 232.02 mg/g for phosphates and 474.61 mg/g for Cr(VI). Additionally, LC-CSP demonstrated excellent reusability, retaining over 83 % of its performance after five cycles. In simulated electroplating wastewater experiments with various interfering substances, LC-CSP maintained high removal efficiencies (>90.72 %) for phosphates and Cr(VI). Post-experiment, enriched water after phosphate desorption was further treated to recover phosphorus resources in complex water environments. Multiple characterization techniques elucidated the adsorption mechanisms of LC-CSP: phosphate adsorption primarily involved ligand exchange, electrostatic interactions, and hydrogen bonding, while Cr(VI) adsorption included electrostatic interactions, hydrogen bonding, and reduction reactions. Finally, fixed-bed simulated wastewater adsorption experiments validated the technical potential of LC-CSP for practical electroplating wastewater management.

Heat and mass transfer performance of multi-solute electroplating wastewater in spray evaporation separation process

Electroplating wastewater is complex in composition and contains many harmful substances. Based on the single droplet heat and mass transfer method, a one-dimensional mathematical model for the evaporation separation heat and mass transfer process of multi-solute electroplating wastewater is established. In order to validate the model, the experimental system of evaporation separation tower is established, and Nusselt numbers corresponding to metal ion solutions are fitted, reliabilities of models are also verified. The maximum relative errors of mathematical models are within 10.0 %. In addition, effects of the type and concentration of metal ions and air inlet temperature on heat and mass transfer characteristics of spray separation tower are investigated. Experimental results show that when the wastewater inlet concentration is the same, the improvement effects of increasing air inlet temperature on evaporation and separation performance from high to low are ZnCl2, CuCl2, and NiCl2 solutions. When the air inlet temperature increases from 90 °C to 130 °C, the evaporation speed of ZnCl2, CuCl2 and NiCl2 solutions increase by 90.3 %, 84.3 % and 45.7 %, respectively. When the air inlet temperature is the same, with the increase of wastewater inlet concentration, the evaporation separation performance of electroplating wastewater in descending order is ZnCl2, CuCl2, and NiCl2 solutions.

Adsorptive removal of cadmium from electroplating wastewater using hybrid composite of thiol-grafted seed gum of Tamarindus indica and Teff hay biocarbon

Abstract This study examined the methods for preparing biocarbon from Teff hay (TBC) and thiol-grafted seed gum of Tamarindus indica (TH@TI-TBC) with the purpose of removing cadmium (Cd) from polluted electroplating waste water. To improve biocarbon adsorption, seed gum and thiol were added in a two-step combination. At a pH of 5.5, the most effective Cd adsorption was seen with TH@TI-TBC (261.47 mg g−1). While comparing to the Freundlich and Temkin models, the Langmuir and pseudo-second-order kinetic models found to be the best fit to the obtained adsorption data. After being treated with electroplating wastewater having 30 mg−1 L of cadmium, TH@TI-TBC was able to remove up to 89 % of the Cd, proving its effectiveness in dealing with adsorptive removal of Cd. Experimental studies and computational analyses revealed that electrostatic interaction and surface complexation were the principal underlying processes for Cd removal by TH@TI-TBC. In addition, an innovative material that can transform the waste into a product for environmental remediation must be developed using the vast amounts of Teff hay that are generated as agro-residue. So, this work proved that TH@TI-TBC can be made from Teff hay biocarbon could be a potential candidate for removing Cd from industrial wastewater.

Treatment of electroplating wastewater using electrocoagulation and integrated membrane.

Electroplating wastewater contains heavy metal ions and organic matter. These contaminants not only endanger the environment but also pose risks to human health. Despite the development of various treatment processes such as chemical precipitation MBR, electrocoagulation (EC) ceramic membrane (CM), coagulation ultrafiltration (UF) reverse osmosis (RO), and CM RO. These methods are only effective for low concentrations of heavy metals and struggle with high concentrations. To address the challenge of treating electroplating wastewater with high heavy metal content, this study focuses on the wastewater from Dongfang Aviation Machinery Processing Plant. It introduces an EC and integrated membrane (IM) treatment process for electroplating wastewater. The IM comprises microfiltration (MF) membrane, nanofiltration (NF) membrane, and RO membrane. Results indicated that under specific conditions, such as a pH of 8, current density of 5 A/dm2, electrode plate spacing of 2 cm, 35 min of electrolysis time, and influent pH of 10 for the IM, removal rates of Zn2+, Cu2+, Ni2+, and TCr in the wastewater exceeded 99%. The removal rates of chemical oxygen demand (COD), suspended solids (SS), total phosphorus (TP), total nitrogen (TN), and petroleum in wastewater exceed 97%. Following a continuous cleaning process, the membrane flux can consistently recover to over 94.3%.

Pengaruh Waktu Kontak dan Debit Aliran Proses Penyisihan Fe dan Mn pada Air Limbah Elektroplating Menggunakan Cascade Aerator

Electroplating wastewater contains high levels of Fe and Mn. One of the treatment methods to remove Fe and Mn in electroplating wastewater is the aeration method using a cascade aerator. the aeration method using a cascade aerator. Aeration is the process of adding oxygen to the water so that it can cause oxidation reactions of Fe and Mn, which will form precipitates. and Mn, which will form Fe(OH)3 and MnO2 precipitates. The gas transfer coefficient (KLa) value during the aeration process was then determined. The Fe and Mn levels before the aeration process were 9.84 mg/L and 4.78 mg/L, respectively. obtained the highest decrease in Fe levels at 240 minutes with a flow rate of 90 mL/s with an efficiency of 70.63% and the highest decrease in Mn levels occurred contact time of 300 minutes with a flow rate of 90 mL/s with an efficiency of 62.76%. 62,76%. The highest gas transfer coefficient (KLa) value occurred at a contact time of 300 minutes with a flow rate of 90 mL/s of 0.0975 KLa/min. The research results obtained have met the quality standards of wastewater according to the Regulation of the Minister of Environment No. 5 of 2014 on Wastewater Quality Standards

Effects of coexisting zinc and nickel ions on crystallization behaviour and properties of spinel synthesised in chromium-containing wastewater

ABSTRACT Electroplating wastewater contains chromium ions, zinc ions, and nickel ions due to the emergence of a multi-layer plating process and unified treatment of mixed wastewater. The effects of coexisting zinc and nickel ions on crystallization behaviour and properties of spinel synthesised in chromium-containing wastewater by ferrite method were investigated in the study. The results indicated that the quality of the supernatant and the stability of synthetic products were barely affected. However, the magnetic property of the synthetic products was significantly increased when the concentration ratio of zinc and nickel ions was appropriate. With the extension of stirring time, the stability of the synthetic product increased, but the crystallinity gradually decreased. Chromium and zinc ions entered the synthetic products preferentially over nickel ions during ferrite synthesis. In addition, the morphology of the synthetic products was irregular and dense, and the lustre distribution was uniform. The distributions of iron, chromium, zinc, nickel and oxygen were overlapped, owing to a single spinel, and the molecular formula of synthetic products was speculated as (3.53 < x < 3.99, 0.2 < y < 0.36, 0.04 < z < 0.05, 0.03 < n < 0.05). Finally, the transport model of metal ions in the mixed wastewater was established, and the synthesis mechanism was revealed.

Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption

Electroplating wastewater contains high amount of heavy metals that can cause serious problems to humans and the environment. Therefore, it is necessary to remove heavy metals from electroplating wastewater. The aim of this research was to examine the electrocoagulation (EC) process for removing the copper (Cu) and lead (Pb) ions from wastewater using aluminum electrodes. It also analyzes the removal efficiency and energy requirement rate of the EC method for heavy metals removal from wastewater. Regarding this matter, the operational parameters of the EC process were varied, including time (20−40 min), current density (40−80 A/m2), pH (3−11), and initial concentration of heavy metals. The concentration of heavy metals ions was analyzed using the atomic absorption spectroscopy (AAS) method. The results showed that the concentration of lead and copper ions decreased with the increase in EC time. The current density was observed as a notable parameter. High current density has an effect on increasing energy consumption. On the other hand, the performance of the electrocoagulation process decreased at low pH. The higher initial concentration of heavy metals resulted in higher removal efficiency than the lower concentration. The removal efficiency of copper and lead ions was 89.88% and 98.76%, respectively, at 40 min with electrocoagulation treatment of 80 A/m2 current density and pH 9. At this condition, the specific amounts of dissolved electrodes were 0.2201 kg/m3, and the energy consumption was 21.6 kWh/m3. The kinetic study showed that the removal of the ions follows the first-order model.

Penyisihan Logam Cr (VI) dari Limbah Cair Elektroplating Menggunakan Mikroalga Chlorella sp. dengan Variasi Penambahan External-Glutathione

Electroplating wastewater containing metal Cr (VI), which has a high toxicity. An alternative treatment is absorbed using microalgae Chlorella sp. Chlorella sp. has the ability to synthesize glutathione phytochelatin (GSH) to respond to the toxic effects of heavy metals. If the micro algae cannot synthesize phytochelatin properly, the cells will die due to exposure to heavy metals in a long contact time. In this study, GSH was added to the metal biosorption process by micro algae Chlorella sp. This study aimed on determining the effect of the adding GSH during the biosorption process. The study was conducted with variations of GSH (0, 5, 10, and 15 mg/L) and variations of contact time (1, 2, 3, and 4 days). The results of this study show that high cell density occurred in the reactor with the addition of GSH 15 mg/L which is 1.72x106 cells/ml. The highest removal of Cr (VI) metal occurred in 4 day contact with the addition of GSH 15 mg/L and obtained a 72% removal efficiency.

Treatment of Electroplating Wastewater Using NF pH-Stable Membranes: Characterization and Application.

Industrial adoption of nanofiltration (NF) for treatment of low-pH wastewater is hindered by the limited membrane lifetime at strongly acidic conditions. In this study, the electroplating wastewater (EPWW) filtration performance of a novel pH-stable NF membrane is compared against a commercial NF membrane and a reverse osmosis (RO) membrane. The presented membrane is relatively hydrophobic and has its isoelectric point (IEP) at pH 4.1, with a high and positive zeta potential of +10 mV at pH 3. A novel method was developed to determine the molecular weight cut-off (MWCO) at a pH of 2, with a finding that the membrane maintains the same MWCO (~500 Da) as under neutral pH operating conditions, whereas the commercial membrane significantly increases it. In crossflow filtration experiments with simulated EPWW, rejections above 75% are observed for all heavy metals (compared to only 30% of the commercial membrane), while keeping the same pH in the feed and permeate. Despite the relatively lower permeance of the prepared membrane (~1 L/(m2·h·bar) versus ~4 L/(m2·h·bar) of the commercial membrane), its high heavy metals rejection coupled with a very low acid rejection makes it suitable for acid recovery applications.

Preparation of Ni(Zn)Cr-LDH/LDO coated magnetic-graphene composites using simulative electroplating wastewaters for oxygen evolution reaction

Electroplating wastewaters (EWs) have to be treated due to their toxic property, which could bring many separation and economic problems. The generation of value-added products using low value and harmful EWs could decrease the economic cost on the treatment and the raw materials. In this work, polyaspartic acid modifying magnetic graphene composite (MG) was firstly prepared with promising magnetic separation and heavy metal ions uptake properties. Ni(Zn)-Cr layered double hydroxides coating magnetic-graphene composites (Ni(Zn)Cr-LDH/MG) were prepared by co-precipitation method using simulative electroplating wastewaters, which were further calcined to form layered double oxides (Ni(Zn)Cr-LDO/MG). The resulting materials were carefully examined by field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometer and electrochemical techniques. The electro-catalysis of the resulting materials towards oxygen evolution reaction (OER) was investigated by various electrochemical methods in 1 M KOH. NiCr-LDO/MG formed at 500℃ showed promising electro-catalysis for OER, with good catalytic stability over long period of 50,000 s. The present results demonstrated that EWs could be reused to fabricating promising value-added catalyst on OER.

Electroplating Wastewater Treatment Method and Development Trend Analysis

Electroplating wastewater is a highly hazardous industrial wastewater with complex composition. For the treatment of electroplating wastewater, the traditional treatment methods include chemical treatment and membrane treatment. According to the requirements of electroplating wastewater treatment and industrial wastewater treatment in recent years, traditional electroplating wastewater treatment technology is difficult to reach new emission standards. The “zero emission” technology of electroplating wastewater has gradually become a new goal of ecological civilization construction. This article starts discussion from this aspect.

Phosphate removal from industrial wastewater through in-situ Fe2+ oxidation induced homogenous precipitation: Different oxidation approaches at wide-ranged pH

Phosphate removal through in-situ Fe2+ oxidation induced homogenous phosphate precipitation has shown its advantages in municipal wastewater treatment. Its feasibility and suitability for phosphate removal in industrial wastewater with wide-range pH variation like electro-plating wastewater were investigated in bench scale experiments using synthetic wastewater and continuous experiment using real wastewater. Bench scale experiments showed that different Fe2+ oxidation approaches worked well for phosphate removal at varied pH conditions. Sole dosing Fe2+ salt with aeration achieved sound phosphate removal at alkaline condition (pH ≥ 8). At neutral pH (6 < pH < 8), transition metallic ions catalytic oxidation is a suitable alternative. Cu2+ exhibited superior catalytic Fe2+ oxidization over Mn2+, Zn2+, and Ni2+. At acid pH (3.0 ＜ pH ≤ 6.0), Fenton reaction oxidation (H2O2 = 5 mg/L) showed its efficiency. At their corresponding optimal pH conditions and with Fe2+/P ratio of 1.8, dosing sole Fe2+ salt, Cu2+ catalyzed Fe2+ oxidation, and Fe2+/H2O2 treatments can achieve the TP discharge limit of 0.5 mg/L. In a 30-day continuous experiment using real electro-plating wastewater (pH 4.9–5.5), in both direct Fe2+/H2O2 treatment and Cu2+ catalyzed Fe2+ oxidation treatment after wastewater pH being adjusted to 7 effluent TP met China's discharge requirement 0.5 mg/L.

Treatment of Industrial Electroplating Wastewater by Electrochemical Coagulation Using Carbon and Aluminum Electrodes

Electroplating wastewater is considered one of the most hazardous liquid wastes due to the presence of high contraction of toxic metals. Consequently, treatment of such wastewater is essential to protect the environment and waterways. Heavy metal ions are frequently of high toxicity and require treatment to the allowable standards for wastewater discharge. Electrochemical methods are more suitable for heavy metals removal due to their ability to reduce metal concentration to less than the permissible limits as well as allowing recovery of valuable metals. The aim of the present study is treatment of real electroplating wastewater. For this purpose, synthetic as well as real electroplating wastewaters were examined using soluble aluminium electrodes and insoluble carbon electrode along with ferric chloride and / or alum as coagulants. Factors affecting this treatment process were studied extensively, namely: current intensity, material of the electrode, pH and time. The obtained results proved that the best removal was achieved at 30 minutes and a potential difference 15 volt for aluminum electrode and 10 volts for carbon electrode. The later was combined with ferric chloride as coagulant. When the synthetic solution was examined by using aluminum electrode, the removal rate reached 97.2%, 97% and 96% for Zn, Cu, and Ni, respectively. By using carbon electrode in combination with ferric chloride, the respective removal rate reached 97.5%, 97.2% and 97.1%. By using the real electroplating wastewater and aluminum electrode, the removal rate reached 80%, 76.6% and 93.4% for Zn, Cu, and Ni respectively and by using carbon electrode and ferric chloride the achieved removal rate was 81.6%, 77.3% and 94.4% successively. It was concluded that the use of carbon electrode with FeCl3 is more suitable than aluminum electrode due to the dissolution of aluminum ions from electrode into the solution.

Application of copper(II) oxide of electrocoagulation products of electroplating waste water as ceramic glaze dyes

This study aims to determine the effect of combustion temperatures and copper(II) oxide concentrations on ceramic glaze color. Electrocoagulation process was carried out using optimum conditions: pH 8, electrocoagulation time of 120 minutes, Al-Fe electrodes, and current density of 1.25 mA/cm2. Experiment variables include combustion temperatures (999, 1060, 1101 °C) and copper(II) oxide concentrations (0.88; 1.76, 2.64, 3.53% ). The results of the coagulant characterization with XRF showed copper(II) content of (22.04 ± 0.73)%. Besides that it also contains of other metals such as Cr, Cd, and Pb however below the detection limit. Coagulant is a metal hydroxide which is dried and calcined formed the oxide. Then, it was applied as a glaze ceramic dye. Based on the analysis of homogeneity using chromameter, the brightness value (L*) increased at the combustion temperature of 999 and 1060 °C, but at a temperature of 1101 °C it decreased. The green color value (a*) decreases when the combustion temperature is raised but the yellow value (b*) increased. When the metal oxide concentration was increased, L* and a* values decreased. While the b* value increased at a concentration of 0.88 to 1.76%, but at a concentration of 2.64 to 3.53% decreased.

Ultra-trace determination of hexavalent chromium by novel two dimensional biphenol-biphenoquinone nanoribbons/silver nanoparticles

In this study, decorated silver nanoparticles on two dimensional (2D) -biphenol-biphenoquinone nanoribbons (AgNPs-BP-BPQ NRs) were prepared for the first time by a novel, fast and simple method. The mentioned compound was then used as modifier for preparation of modified graphite paste electrode (GPE/AgNPs-BP-BPQ NRs) for indirect voltammetric determination of carcinogen hexavalent chromium (Cr (VI). Peak current of BP/BPQ redox system was decreased in the presence of Cr (VI), hence, this decrease in peak current was used as the electroanalytical signal for quantitative determination of Cr (VI). Moreover, the redox reaction of Cr (VI) and BP was investigated in this study for the first time and the product was characterized. Different techniques such as field emission electron microscopy, Energy-dispersive X-ray spectroscopy, transmission electron microscopy, atomic force microscopy and fourier transform infrared spectroscopy were performed for characterization of the AgNPs-BP-BPQ NRs. Different electrochemical methods, such as cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry, were employed to study the behavior of Cr (VI) on the proposed modified electrode. Under the optimum conditions, the calibration curve was liner in the ranges of 8.0 × 10−11 to 1.0 × 10-8, 1.0 × 10-8 to 1.0 × 10-6 and 1.0 × 10-6 to 1.0 × 10-4 M with a detection limit of 2.0 × 10-12 M. Finally, this sensor was successfully used for determination of Cr (VI) in tap water, river water and electroplating waste water samples.

Ceramic Membrane Coupling Process for Advanced Treatment of Electroplating Wastewater

Electroplating wastewater has attracted wide attention because of its large amount and complex components. It contains a variety of heavy metals and organics that are harmful to people’s healthy and the environment. With the continuous improvement of environmental protection requirements, the emission standards for electroplating pollutants have also been improved. Therefore, the advanced treatment of electroplating wastewater has become a hot spot in the current research. Membrane separation technology has been widely used in the advanced treatment of electroplating wastewater, especially ceramic membrane technology which is more competitive in practical application due to its unique advantages. In order to realize the advanced treatment of electroplating wastewater, the commonly used advanced treatment process and its existing problems were introduced firstly. Then the development of ceramic membrane technology in advanced treatment was discussed. And finally, a ceramic membrane coupling process for the advanced treatment of electroplating wastewater was proposed, which has good economic and social benefits.

Precious Metals Recovery from Electroplating Wastewater: A Review

Metal bearing electroplating wastewater posts great health and environmental concerns, but could also provide opportunities for precious and valuable metal recovery, which can make the treatment process more cost-effective and sustainable. Current conventional electroplating wastewater treatment and metal recovery methods include chemical precipitation, coagulation and flocculation, ion exchange, membrane filtration, adsorption, electrochemical treatment and photocatalysis. However, these physico-chemical methods have several disadvantages such as high initial capital cost, high operational cost due to expensive chemical reagents and electricity supply, generation of metal complexes sludge which requires further treatment, ineffective in diluted and/or concentrated wastewater, low precious metal selectivity, and slow recovery process. On the other hand, metal bio-reduction assisted by bioactive phytochemical compounds extracted from plants and plant parts is a new found technology explored by several researchers in recent years aiming to recover precious and valuable metals from secondary sources mainly industrial wastewater by utilizing low-cost and eco-friendly biomaterials as reagents. Extract of plants contains polyphenolic compounds which have great antioxidant properties and reducing capacities, able to reduce metal ions into zerovalent metal atoms and stabilize the metal particles formed. This green bio-recovery method has a value added in their end products since the metals are recovered in nano-sized particles which are more valuable and have high commercial demand in other fields ranging from electrochemistry to medicine.

Development of a rapid and reliable liquid-liquid extractive method for the effective removal of chromium(VI) from electroplating waste water and tannery effluents

A rapid and selective liquid-liquid extractive system is developed for extraction of Cr(VI) by employing N-n-OCA reagent and xylene as solvent. Quantitative extraction of Cr(VI) is observed in the concentration range of 0.4 to 0.7 M HCl. The extracted [Cr(VI)-N-n-OCA] complex from the organic phase was back extracted by 6.0 M ammonia (3 × 10 mL) and spectrophotometrically quantified. Various parameters were explored to study their influence on quantitative extraction of Cr(VI) by varying N-n-OCA concentration, equilibration time, effect of diluents, acid concentration and diverse ions. Stoichiometry of the extracted complex showed 1: 1 ratio of acid and amine. The relative standard deviation of the developed method is 0.09 with respect to calibration range 0.2 to 0.8 μg mL–1. The validity of the proposed method was checked by applying it to the associated and toxic metals in binary, synthetic mixtures and ternary effluents.

Nanopraticle Ferriferous Hydrosol as an Advanced Reagent for Waste Water Treatment

A new procedure for electroplating waste water treatment using a waste iron scrap by-product for nanoparticle ferriferous hydrosol (FFH) preparation is presented. FFH which contains Fe(II) and Fe(III) was employed for neutralization and heavy metal removal from electroplating wastewater as well as for decontamination of concomitant pollutants such as phosphates, organic compounds, residual oils, dyes and detergents. It is possible due to the simultaneous operation of several different mechanisms: sorption, coagulation, reduction, fertilization and etc. The method is suitable for the purposes of waste water treatment and disposal in compliance with environmental laws and is implemented in some East and West European countries. The results were proved in accredited laboratories in various countries. According to the composition of its water extractable fraction, remaining waste sludge could be safely deposited in urban waste repositories or used as a raw material for production of various technically useful products such as ceramics, pigment, etc. Treated water may be reused in technological processes.

FABRICATION OF CONTINUOUS ADSORBER FOR DIRECT TREATMENT OF ELECTROPLATING WASTE WATER USING DRIED FLOWER WASTE

Water is an indispensable part of our lives. The waste water released from industries has the potential to be hazardous to human health. The safe and effective disposal of industrial waste water is thus a challenging task for industrialists and environmentalists. The industrial waste water released as effluent contains heavy metal ions such as cadmium, lead, nickel, chromium etc., which are toxic in nature. In this project, removal of Nickel – an important toxic metal coming from electroplating waste water, using flower waste (whose management is also important) as bio-sorbent was studied and carried out batch wise, continuously , finally fabricating a continuous adsorber that can handle electroplating waste directly. In order to remove color and other impurities Granulated Activated Carbon (GAC) is also incorporated in the adsorber. In batch study, the effectiveness of adsorbents (i) Dried flower waste (ii) Granular activated carbon prepared from flower waste sequentially used in treating metal ion solution was determined. The efficiency of nickel removal was studied in both batch and continuous adsorber and compared.