The application of agricultural wastes for heavy metals adsorption: A meta-analysis of recent studies

Numerous studies have been carried out to investigate the suitability of various agricultural wastes as biosorbent for heavy metals removal. Previous published reviews on heavy metal removal by agricultural waste-based biosorbent were limited to narrative and systematic reviews, with no statistical analysis to compare outcomes across different biosorbents sources. In this work, meta-analysis technique was applied to identify gaps in contemporary biosorbents research. A meta-analysis was undertaken using several packages of R programme on publications over the last five years to evaluate the capability of eleven different types/components agricultural wastes for the adsorption of eight heavy metal. Based on the findings, agricultural wastes have the potential to be employed for heavy metal adsorption from aqueous media in general. However, the disparities in the findings suggest that when utilising different types of raw biomass as adsorbents, modifying the biomasses into carbon-enriched forms would be a preferable option. [Display omitted] •Diverse review articles on biosorbents but not a single statistical analysis yet•Used “R” programme for meta-analysis of 75 selected articles of last 5 years•Various agricultural wastes were compared for their adsorption capabilities.•Agricultural wastes exhibited varying levels of heavy metals removal efficiency.•Modified agricultural wastes might be better sorbents than using them directly.