Evaluation of the Performance of the Electrocoagulation Process for the Removal of Water Hardness

Abstract

One of the biggest problems of water with high concentrations of calcium is its susceptibility to causing scaling in industrial equipment (boilers, heat exchangers, pipes, reverse osmosis membranes, storage tanks, etc.). The purpose of this study was to evaluate a recently built filter press (EC) type electrocoagulation reactor and investigate the efficiency of water hardness removal. The electrocoagulation (EC) reactor has been evaluated in batch mode using electrodes of aluminum (Al) and connected to a direct current power supply in a monopolar way. To evaluate the performance of the reactor, a synthetic solution with a concentration similar to that of brackish water was used. A factorial design was applied to investigate the influence of the electrical potential applied to the electrocoagulation cell at the levels of 3, 5, 7, and 9 V, and initial calcium hardness of 540.2 and 914.60 mg/L CaCO3 at room temperature in 60 treatment minutes. The results revealed that the electrical potential applied to the electrocoagulation cell was the most significant factor in hardness removal, within the experimental ranges studied. The results showed that electrocoagulation at an electric potential applied at 9 volts and an initial concentration of 7400 mg/L allowed a higher hardness removal efficiency (25.83%). the pH of the solution increased throughout the process. The energy consumption ranged between 4.43 and 42 kW.h/m3 depending on the conditions of the factors. It has been shown that during the treatment process a layer of dense and compact calcium carbonate precipitate is formed on the surface of the cathode.

Electrocoagulation Process as a Consolidated Technology in the Treatment of Industrial Effluents and as a Promising Process in the Treatment of Effluents Generated by Car Washes: A Brief Review

“…If discharged into the environment without proper treatment, these effluents can affect the quality of human, animal, plant, and microbiological lives, and are characterized as important polluters and open sewers. , In addition, the discharge of these effluents containing residual detergents causes foaming, which reduces the dissolved oxygen levels in the waters (Hashim and Zayadi) and, associated with the chemical composition affecting the values of the COD indexes, can cause varied and complex negative impacts on animals and plants living in the environment. − …”

“…The effluents generated from car, truck and other vehicle wash processes consist of waters that can contain various types of contaminants, such as detergents and surfactants, phosphates, metallic species, and hydrocarbons, as well as high TSS and BOD levels. All these factors directly influence the values of the COD, OG, turbidity, as well as color indexes, and therefore the quality of the discharged water. ,,− …”

Research Progress on Novel Electrochemical Descaling Technology for Enhanced Hardness Ion Removal

“…Electrocoagulation is a promising method for removing hardness from water [87]. The flocs formed during the electrocoagulation process offer ample precipitation zones for hardness removal, overcoming the limitations of the cathodic area on electrochemical descaling.…”

Electrocoagulation using aluminum electrodes as a sustainable and economic method for the removal of kinetic hydrate inhibitor (polyvinyl pyrrolidone) from produced wastewaters

“…Electrocoagulation is an electrochemical technique for water treatment based on the anodic dissolution of a sacrificial metal, by averaging the related reactions such as the cathodic reduction of water that gives hydroxo-metal complexes, which ensure the destabilization and the adsorption of the dissolved pollutants and the flocculation of the aggregates formed (Ghernaout, 2019;Romani et al, 2020;Jovanović et al, 2021;Lucakova et al, 2021;AlJaberi et al, 2022;Lu et al, 2022;Medina-Collana et al, 2023). It is considered a complex electrochemical process with the involvement of several synergistic mechanisms contributing to the elimination of water pollution (Bensalah, 2011;Orescanin et al, 2014;Abdulrazzaq et al, 2021;Elkhatib et al, 2021;Idusuyi et al, 2022).…”

“…The pitting corrosion of aluminum is much more vulnerable than other metals. The addition of certain supporting electrolytes such as NaCl, can reduce the passivation of the electrodes and improve ionic conductivity of the solution (Mansouri et al, 2011a(Mansouri et al, , 2012Acharya et al, 2022;Morales-Figueroa et al, 2022;Medina-Collana et al, 2023). The use of an alternating current source with variable pulse frequency can also prevent the formation of deposits on the surface of the electrodes (Asaithambi et al, 2021;Othmani et al, 2022).…”