Trace element removal from wastewater by agricultural biowastes: A data analysis on removal efficacy and optimized conditions

Valorization of agricultural biowastes to biosorbents provides an excellent opportunity to recycle these wastes into valuable products and filtration of contaminants, especially potentially toxic trace elements in aquatic ecosystems. Water contamination with potentially toxic trace elements is a widespread global issue. Various agricultural biosorbents have been tested to remove trace elements from wastewater. Despite abundant research, there are scarce studies regarding the critical data analysis on trace elements removal efficiency by agricultural biowastes under various conditions. This review critically delineates the data analysis of recent literature published from 2018 to 2024 for a critical comparison of different agricultural biosorbents and the applied conditions to remove trace elements from aqueous media. Data analysis (based on 1188 observations) revealed that the mean trace element removal by agricultural biowaste-derived biosorbents from contaminated water was 75 %, ranging from 2 to 100 %. The most frequently reported removal efficiencies of agricultural biosorbents were 90–100 %. Notably, few agricultural biosorbents such as banana peel demonstrated the highest removal efficiency of 97 %, followed by cassava peels at 92 %, emphasizing the significance of recycling these materials for sustainable trace element removal from wastewater. Data analysis revealed that the trend for trace element removal from wastewater follows a descending order, with zinc exhibiting the highest removal rate at 81 %, followed closely by lead at 80 %. This trend continues with arsenic at 75 %, nickel and cadmium both at 70 %, and so forth. Thus, agricultural biosorbents play a pivotal role in this process, showcasing their potential in waste valorization and environmental remediation. Hence, the present review article is expected to contribute towards the comparative efficiency of various agricultural biosorbents, and the selection of the best biosorbents, depending on applied conditions for trace element removal from targeted wastewater treatment facilities.