Abstract
Wastewater generation and treatment is an ever-increasing concern in the current century due to increased urbanization and industrialization. To tackle the situation of increasing environmental hazards, numerous wastewater treatment approaches are used—i.e., physical, chemical, and biological (primary to tertiary treatment) methods. Various treatment techniques being used have the risks of producing secondary pollutants. The most promising technique is the use of different materials as adsorbents that have a higher efficacy in treating wastewater, with a minimal production of secondary pollutants. Biosorption is a key process that is highly efficient and cost-effective. This method majorly uses the adsorption process/mechanism for toxicant removal from wastewater. This review elaborates the major agricultural and non-agricultural materials-based sorbents that have been used with their possible mechanisms of pollutant removal. Moreover, this creates a better understanding of how the efficacy of these sorbents can be enhanced by modification or treatments with other substances. This review also explains the re-usability and mechanisms of the used adsorbents and/or their disposal in a safe and environmentally friendly way, along with highlighting the major research gaps and potential future research directions. Additionally, the cost benefit ratio of adsorbents is elucidated.
Highlights
Numerous studies and efforts have been made for environmental protection against potentially toxic elements (PTEs)
They usually consist of lignin and cellulose as the main components and have -OH and -COOH groups. These groups can be combined with metal ions by providing electron pairs to form complexes. Agricultural wastes such as grape straw, tea and coffee grounds, nutshells, papaya and plant leaves, waste grains, algae, crab apple shells, rice bowls, and sunflower plants have been used by many scientists to remove PTEs such as As, Cd(II), Cr(IV), Hg, Pb, and Ni
Agricultural waste-derived adsorbents can be modified by different chemical pretreatments to increase the potential of functional groups, thereby increasing the adsorption capacity of adsorbents [66]
Summary
These include copper (Cu), mercury (Hg), cadmium (Cd), zinc (Zn), tin (Sn), iron (Fe), lead (Pb), silver (Ag), manganese (Mn), chromium (Cr), cobalt (Co), arsenic (As), aluminum (Al), and nickel (Ni) [13,14] (Supplementary Information Table S1) Due to their persistence, higher mobility, and solubility, wastewater containing these PTEs is not properly treated and discharged into freshwater resources with various environmental and health effects. Phenols, herbicides, petroleum, dyes, oils, biphenyls, fats, proteins, starches, and medicines, while inorganic pollutants contain chemical fertilizers, PTEs, and excessive nutrients They cause water quality deterioration and serious environmental problems [18,19]. This review aims to provide information about the major agricultural and non-agricultural material-based adsorbents Their mechanisms of pollutant removal are mentioned, along with possible ways to enhance their efficacy by modification or treatment with other substances. This review explains their prospects of re-usability and mechanisms of safe disposal
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
