Optimization of Mn removal from aqueous solutions through electrocoagulation

Crude oil wastewater treatment by electrocoagulation in a continuous process with polarity switch

The influence of the distance between electrodes, electrical current, and flow rate of emulsified crude oil in water effluent through an electrocoagulation reactor was studied. Power switch at an interval of 30 s was used to reduce electrode passivation. The output variables were power consumption, pH, and oil removal from effluent. There was no significant change in the output variables with the working time of the reactor. The final pH was between 7.5 and 9.5 depending on the input variables. It increases with higher electrical current and tends to decrease with increased flow rate. Increasing electrical current tends to increase while increasing either distance between electrodes or the flow rate tends to reduce oil removal. Using a 2.88 L reactor, it is possible to treat 7.12 L of effluent in one hour, removing 78% of the crude oil, keeping final pH at 8.3, and this system will have an energy consumption of 21.6 kWh.

Removal of inorganic pollutants using electrocoagulation technology: A review of emerging applications and mechanisms

Electrocoagulation (ECoag) technique has shown considerable potential as an effective method in separating different types of pollutants (including inorganic pollutants) from various sources of water at a lower cost, and that is environmentally friendly. The EC method's performance depends on several significant parameters, including current density, reactor geometry, pH, operation time, the gap between electrodes, and agitation speed. There are some challenges related to the ECoag technique, for example, energy consumption, and electrode passivation as well as its implementation at a larger scale. This review highlights the recent studies published about ECoag capacity to remove inorganic pollutants (including salts), the emerging reactors, and the effect of reactor geometry designs. In addition, this paper highlights the integration of the ECoag technique with other advanced technologies such as microwave and ultrasonic to achieve higher removal efficiencies. This paper also presents a critical discussion of the major and minor reactions of the electrocoagulation technique with several significant operational parameters, emerging designs of the ECoag cell, operating conditions, and techno-economic analysis. Our review concluded that optimizing the operating parameters significantly enhanced the efficiency of the ECoag technique and reduced overall operating costs. Electrodes geometry has been recommended to minimize the passivation phenomenon, promote the conductivity of the cell, and reduce energy consumption. In this review, several challenges and gaps were identified, and insights for future development were discussed. We recommend that future studies investigate the effect of other emerging parameters like perforated and ball electrodes on the ECoag technique.