Non-conventional absorbers: sustainable alternatives for wastewater treatment

Abstract

This article shows a revision of the non-conventional absorbers employed for the removal of water pollutants. A brief description is made on the conventional absorbers in order to distinguish them from the non-conventional ones. Conventional absorbers are those natural or synthetic materials which employment is contingent with a treatment process so that they can be activated, such as carbon, clays, membranes, etc. After using these materials, they are able to be regenerated. Non-conventional absorbers are alternate materials (biopolymers or parts of plants); they should not necessarily be subject to a previous treatment to be activated; however, activation improves their absorption capacity. Sources studied for obtaining the materials employed as non-conventional absorbers include agroindustrial wastes, food industry wastes, and plant species which application is restricted or has no application at all. Different studies have shown that the employment of natural materials as non-conventional absorbers allows minimizing the organic discharge of a river contaminated with metals, dyes, pesticides, and other organic compounds known as emerging compounds. The fields of study for non-conventional materials emerge as a need for the design of sustainable process for the wastewater treatment; for this reason, the study and revision of non-conventional materials are of special interest to go deeper and propose alternative according to the existing needs.