The impact of acid activation on manganese ion extraction from natural water and industrial wastewater

Increased manganese concentration is characteristic not only of fresh water, but also of wastewater. Metal enters wastewater as a result of industrial activities such as manganese oxide ore beneficiation, galvanic cell production, and organic synthesis. Manganese compounds are strong poisons with pronounced cumulative effects. The effect leads to enzyme blockage, thyroid gland suppression, and accumulation in the liver and kidneys. Sorption method is used to remove manganese from natural water and industrial wastewater. This method can remove contaminants to any desired residual concentration. However, to mitigate the consequences of anthropogenic impact on the environment in the context of growing water consumption, the use of new, efficient materials is required. Currently, modified natural clay materials are being used for the purification of natural water and industrial wastewater. The authors investigated the extraction of manganese ions from aqueous solutions using modified diatomite. The diatomite was treated with a hydrochloric acid solution to increase the number of surface adsorption sites. Chemical modification of clay sorbents increases the pore space and specific surface area, which leads to an increase in sorption capacity. The experimental results showed an increase in the exchange capacity of the modified H-form: 1.45 mg/g compared to the native form – 0.63 mg/g. The values of maximum sorption capacity were 0.58 mg/g for the native form and 1.19 mg/g for the H-form. The optimal conditions for the sorption extraction of manganese ions were determined: 15.7 % for the native form and 63.2 % for the modified H-form.

sorption, natural sorbents, modification with hydrochloric acid, modified diatomite, manganese ions, Langmuir adsorption model, Freundlich adsorption isotherm, Temkin adsorption model