Biotransformation of Citrus Waste-II: Bio-Sorbent Materials for Removal of Dyes, Heavy Metals and Toxic Chemicals from Polluted Water

Abstract

Industrial processes and anthropogenic activities generate huge amounts of wastes in the form of chemicals, such as heavy metals, dyes, fertilizers, pharmaceutically active chemicals, battery effluents and so on. When these chemicals are left untreated and discarded in the ground or surface waters, they not only cause pollution and harm the ecosystem but also cause toxic effects on the health of human beings, animals and food crops. There are several methods of removal of these toxic materials from the wastewaters, and adsorption by bio-sorbents has been demonstrated as one of the most inexpensive, efficient and convenient methods. Citrus is one of the largest grown fruit crops in the tropical and subtropical regions on the planet. After processing of the fruits at food processing industries, approximately half of the fruit mass is discarded as waste, which causes a number of pollution problems. Alternately, this biomass can be converted to bio-sorbents for the removal of harmful and toxic chemicals from the industrial effluents and wastewaters. The first part of this article contains a thorough review on the biotransformation of citrus waste for the production of biofuel and valuable compounds by fermentation involving microorganisms. The second and concluding part reviews the recent progress in biotransformation of citrus waste biomass (that may be remaining post-extraction of valuable compounds/biofuel generation) into efficient adsorbent substrate materials and their adsorption capacities. The article also includes the details of the synthesis process and mechanisms of adsorption processes.

Exploring hydrodynamic cavitation for citrus waste valorisation in Malta: from beverage enhancement to potato sprouting suppression and water remediation

“…Unprocessed peel is a low-to-moderately effective bio-sorbent, but its adsorption is enhanced following physicochemical, or biological treatments ( Michael-Igolima et al, 2023 ). This enhanced adsorption makes it effective at removing contaminants such as heavy metals, nitrates, and ammonia from water ( Dey et al, 2021 ; Mahato et al, 2021 ). We have assessed the adsorption of copper ( Figure 2A ), as well as nitrates ( Figure 2B ) and nitrites ( Figure 2C ) on unprocessed and HC-processed peel, with biosorption parameters reflecting favourable binding ( Supplementary Tables S1, S2 ) in harmony with previous works ( Feng et al, 2009 ; Izquierdo et al, 2013 ; Abdulrazak, 2016 ; Romero-Cano et al, 2016 ; Amin et al, 2017 ; Surovka and Pertile, 2017 ; Özkan et al, 2017 ; Amin et al, 2019 ; Safari et al, 2019 ; Kumar and Raju, 2020 ; Amirsadat et al, 2022 ; Shahaji et al, 2023 ).…”

Agriculture By -Products Wastes as Low-Cost Bio-Sorbents for Heavy Metals Removal from Industrial Waste Stream, Short Review

“…Incorporating of phenolic substances into the bio-sorbent improves binding with the metal ions [30]. Esterification, phosphorylation, methylation and hydrolysis of amide and carboxylate groups are significant modification methods [31]. Al-Qodah et [32]developed an effective bio-sorbent from green algae after modifying it through phosphorylation, according to the author the phosphorylation process increases the phosphate group on the surface and quiescently the binding efficiency of the metal ion with the surface is significantly enhanced.…”

Special Issue “Applications of Biosorption in Wastewater Treatment”

“…One of the great advantages of the biosorption process is that the sorbent material can be very varied; thus, it is possible to use waste materials that lack an apparent utility. As an example of this, we have the article by Mahato et al [2] in this Special Issue. This review shows the application of biomass from citrus waste for the elimination of a great diversity of pollutants.…”