Vinasse is acidic, dark brown wastewater obtained as a residue from the alcohol distillation process, the main component of which is water, in addition to mineral nutrients and a high organic load. Electrocoagulation (EC) is a technology that generates coagulating substances in situ by oxidizing sacrificial anodes through an electric current applied to the electrodes. During the last decade, the electrocoagulation process has been intensively investigated in several reviews, due to its ease of operation, versatility, sustainability and low environmental impact. The objective of the present work has been to make a general review of the EC process, its principle, reaction mechanism and operating parameters involved in the electrocoagulation process. In this research, the PRISMA method was used for the analysis of articles from different databases such as Scopus, ScienceDirect and Google Scholar. This review collects numerous studies of the EC process in stillage wastewater treatment and makes a comparison between these experimental results mainly in terms of chemical oxygen demand removal. In addition, this review makes a comprehensive analysis of EC coupled to other processes, taking into account their operating parameters and stillage contaminant removal efficiency. The conclusion of this research points out that electrocoagulation coupled with other treatment processes is very necessary because it reduces energy consumption and increases the rate of pollutant removal from wastewater.

Brackish water is an important source of water resources with lower salt content than seawater. Desalination is a very important treatment to remedy the scarcity of fresh water throughout the world. In this work, it has been proposed to desalinate brackish groundwater using a commercial...

In the present study, a calcium alginate bead adsorbent was prepared from brown algae (Macrosystis pyrifera) and was used for removal of Pb⁺², Cu⁺², and Sb⁺³ ions from aqueous solutions, using a fixed bed column. The initial concentration of metal ions, mass of adsorbent, recirculation flow, hydrodynamic cavitation, and contact time were examined, and the adsorption kinetics and isotherms were systematically studied. The Taguchi five-factor methodology was used for the development at three levels of experimentation. Experiment N° 24 (concentration, 10 mg/L; flow rate, 10 mL/s; adsorbent mass, 10 g; hydrodynamic cavitation with maximum air flow, and treatment time 240 min) resulted in the maximum removal of 92%, 78%, and 16% of lead, copper, and antimony ions, respectively. The average rate constants corresponding to pseudo-second-order kinetics for lead, copper, and antimony ions were 5.3 × 10⁻³, 1.4 × 10⁻³, and 7 × 10⁻⁵ g.mg⁻¹min⁻¹, respectively. In the adsorption process, they closely approximate to Langmuir and Freundlich isotherms, with adsorption capacities for Pb²⁺, Cu²⁺, and Sb³⁺ of 7.60, 2.07, and 0.37 mg/g, respectively, with good bioadsorption affinity of Pb > Cu > Sb. It was demonstrated that the bioadsorption equipment, with proper control of the factors, achieves concentration values of lead and copper ions below the current environmental regulations. The results of these studies indicated that calcium alginate is a promising adsorbent for separating and recovering heavy metal ions from contaminated water, although further research is needed for antimony ions.

Given the problems related to drinking water supplies in rural and economically disadvantaged regions, point-of-use disinfection technologies are a viable alternative to improve access to drinking. Electrochlorinators are devices that produce chlorine-based disinfectants onsite via the electrolysis of a sodium chloride solution. In this research, we have constructed an innovative laboratory-scale three-compartment cell that includes two ion exchange membranes, fixed between two electrodes; in the anodic compartment, an acidic mixture of chlorine-based species (Cl₂, HClO, HCl and ClO⁻) is obtained, and, in the cathodic compartment, an alkaline solution is present (NaOH and hydrogen gas), while the central compartment is fed with a sodium chloride solution. The Taguchi methodology was used to examine the impact of the process operating conditions on the results obtained. The effects of the electrical potential levels (4.5, 6 and 7 V), electrolysis times (30, 60 and 90 min) and initial sodium chloride concentrations (5, 15 and 30 g/L) on the physical and chemical characteristics (concentrations of available chlorine and sodium hydroxide and pH of the solutions) and energy consumption were investigated. Variations in the electrical potential significantly influenced the concentration levels of active chlorine and sodium hydroxide produced, as well as the pH values of the respective solutions. The most favorable conditions for the production of electrolyzed water were an electrical potential of 7 volts, an electrolysis time of 90 min and a concentration of 30 g/L of sodium chloride, which was verified by ANOVA. The maximum concentration of active chlorine reached 290 mg/L and that of sodium hydroxide reached 1450 mg/L without the presence of hypochlorite ions under the best synthesis conditions. The energy consumption was 18.6 kWh/kg Cl₂ and 4.4 kWh/kg NaOH, while the average electric current efficiency for sodium hydroxide formation reached 88.9%. Similarly, the maximum conversion of chloride ions reached 24.37% under the best operating conditions.