An Overview of Adsorption Technique for Heavy Metal Removal from Water/Wastewater: A Critical Review

Abstract

Heavy metal pollution in the environment and effects on human health is within the most important issues. Because of continuous deterioration of water quality and persisting contamination level it has been observed and concerned by the scientists. Recently, to remove heavy metals from water/wastewater using various methods has been extensively studied. In conventional technologies, heavy metal removal/remediation is provided expensive because of non-regenerable materials used and high costs. Adsorption processes are being widely performed by several researchers for this purpose and various materials have been frequently used as adsorbent. It has been proved that adsorption is an effective method for purification, because of significant advantages including stability, utility, low-cost, ease of operation and performance. As adsorption technology is reduce the heavy metal ions concentrations to very low levels and because of using various low-cost adsorbent materials including biosorbents, clays, activated carbons, zeolites, metal oxides, it has major advantages. Metal adsorption onto adsorbent material, especially on agricultural wastes is a rather complex process because it is controlled by various factors. This process includes complexation, chemisorption, adsorption-complexation on surface and pores, micro precipitation, ion exchange. When used biological materials for adsorption process, some functional groups including sulphydryl, amido, hydroxyl and carboxyl, attach metal ions from water. This paper reviews the available adsorbent materials that have been used to heavy metal removal from water/wastewater and evaluates this technique advantages. Herein, the biosorbents such as banana peel, astragalus, chestnut sheel, natural adsorbents including clay also some artificial materials, like carbon-nanomaterials, zeolites, metal oxides, are reviewed as adsorbent materials for removal of different heavy metal ions like As(V), Pb(II), Cd(II), Cr(VI), Th(IV) and Eu(III) from water/wastewater.

Improved qualitative properties of pear pekmez by natural zeolite treatment during production process

“…The reduction of F − , Cl − , Br − anions and K + cations and access to Na + and Mg ++ cation concentrations in pekmez samples obtained from after zeolite treatments to the pear juices appear as a result of an ion exchange process. It is well known that zeolites acts as ion exchange materials due to their structural properties with high specific surface areas and high ion‐exchange capacity and widely used for metal ions removal from the aqueous medium (Ince & Ince, 2017). There is no available data held on usage of zeolites on pear pekmez.…”

Combined Wastewater Treatment from Manganese Phosphate Coating: Coagulation-Ozonation-Fenton Reaction-Sorption

“…The methods of industrial wastewater treatment include precipitation techniques with the use of calcium compounds [7,8], coagulation methods with the use of aluminum and iron compounds [9,10], treatment with the use of membrane methods [11], adsorption processes using zeolites or biomass [12], processes using nanofiltration or reverse osmosis [13,14], electrodialysis [15][16][17], photocatalytic methods [18], ultrafiltration [19], purification with the use of activated carbon [20][21][22] as well as techniques of advanced oxidation with the use of ozone, hydrogen peroxide, UV radiation and Fenton's reagents [23,24]. Beside chemical methods, we should also list physical methods in wastewater treatment, such as sedimentation [25] or processes related to the equalization of wastewater flow, which mainly consist of buffering by introducing equalizing devices or such retaining the flowing wastewater [26].…”

Eco-Friendly β-cyclodextrin and Linecaps Polymers for the Removal of Heavy Metals

“…Several techniques, based on different physicochemical processes, can be exploited to achieve metal detoxification, including chemical precipitation [6,7], ion-exchange [8,9], membrane filtration (such as ultra- and nanofiltration, electrodialysis and reverse osmosis) [10], floatation [11], coagulation [12], electrochemical methods [13] and biological and chemical adsorption [14,15]. Currently, wastewaters are purified from metals and organic pollutants mainly by treatment with precipitating agents, membranes, ion-exchange resins, activated carbon and biological agents [16].…”