Review of Heavy Metal Adsorption Processes by Several Organic Matters from Wastewaters

Abstract

Heavy metal contamination of natural rivers and wastewaters is a problem for both the environment and human society. The accumulation and adsorption of heavy metals could happen with several organic and inorganic matters, but the most used adsorbents are (biological and chemical) organic compounds. This review article presents the basics of heavy metal adsorption on several organic surfaces. There are many organic matters, which seem to be useful as agents for heavy metal adsorption. All of the cited authors and articles present the adsorption kinetics by the most used isotherm models (such as Langmuir and Freundlich isotherms). By comparing several research results presented by a pre-selected assortment of papers, we would like to give an overview of the microbiological, organic chemical, and other surface adsorption possibilities. We draw conclusions for two new adsorption fields (adsorption with biosorbent and artificial materials). We present an optional possibility to study adsorption kinetics, efficiency and regeneration methods to successfully conclude the heavy metal treatment process, and we make some recommendations about the efficient water usage calculations using the water allowance coefficient (WAC) indicator.

Chromium Speciation in Zirconium‐Based Metal–Organic Frameworks for Environmental Remediation

“…From the adsorbate-adsorbente lectrostatic interaction point of view,i ti s foreseen that the Cr III andC r VI speciesb ehave in different way, since they will be immobilized at different points of the adsorbentchemical structure. Adsorption isothermsf or UiO-66-R (R =-H, -NH 2 ,-(OH) 2 ,-Hdef, -NH 2 -def,-(OH) 2 -def) compoundsw ere obtained from batch experiments of chromium solutions with concentrations ranging from 1t o1 00 ppm, as shown in Figure2.T he isotherm curves were fitted by nonlinearL angmuir [63] and Freundlich [5,63,64] models, described in the supplementary information. The experimental data, as well as the modelled adsorption isotherms, are shown in Figure 2.…”

“…[1][2][3] Apart from their high toxicity,e ven at very low concentrations, heavy metalsa re non-biodegradable, highly mobilea nd present al ong-term bio-persistence, which makes them an increasing environmental and health concern. [3][4][5] Within the heavy metals, chromium is particularly dangerous as it is usually present as highly soluble and mobile hexavalent chromate ([Cr VI O 4 ] 2À )a nd dichromate ((Cr 2 VI O 7 ) 2À )o xyanions, which are genotoxic, mutagenic,t eratogenic and carcinogenic. [2] The scientific community is paying attention to this environmental problem, focusinge fforts on the development of bifunctional materials that are ablet ow ork as Cr VI sorbents and Cr VI to Cr III reducers.…”

Examination of Short Supply Chains Based on Circular Economy and Sustainability Aspects

“…Sustainability of food chains can be measured by the following indicators: Life cycle analysis (LCA), carbon accounting, material flow analyses, ecological foot-printing, food miles, Hazard Analysis and Critical Control Points (HACCP) studies, stakeholder dialogue and surveys and converting impacts into financial analysis [25,35]. In terms of environmental impact, the importance of the water allowance coefficient (WAC)-as an indicator based on water footprint-is also increased [36].…”

Reduced Graphene Oxide-Based Foam as an Endocrine Disruptor Adsorbent in Aqueous Solutions

“…Later the rectangular hyperbola function form in Equation (2) was used to determine the maximum % adsorbed compounds (% R max ) for each analyte through non-linear regression analysis. The k ’ is a constant related to desorption [ 35 , 36 , 37 ].…”