Potential Enhancement of Soil and Sediment Remediation and Bioremediation by Using Biochar Amendment: A Systematic Review

Abstract

Biochar has gained attention as a viable strategy for soil and sediment remediation in Southeast Asia due to its ability to adsorb heavy metals and organic pollutants, enhance soil fertility, and support sustainable agriculture. This review synthesizes biochar research conducted in Southeast Asia from 2014 to 2024, focusing on pollutant categories, biochar types, and environmental functions. A bibliometric analysis of 103 Scopus-indexed publications assessed research trends, keyword co-occurrences, and institutional and national collaboration networks. Results show an annual publication growth rate of 17.2%, with China, Malaysia, and Sri Lanka as leading contributors. Keywords "biochar," "soil remediation," "heavy metals," and "engineered biochar" appeared most frequently, reflecting emphasis on contaminant immobilization and biochar optimization. Lead, cadmium, and organic pollutants were the primary contaminants addressed. Although engineered and modified biochar has demonstrated enhanced performance for multi-contaminant remediation, significant research gaps remain in the mechanistic understanding of pollutant interactions, large-scale field validation, cost-effectiveness, and integration with complementary technologies. This review represents the first bibliometric evaluation of biochar use for soil and sediment remediation in Southeast Asia and offers insights to support future research direction, collaborative networks, and policy development.