A global systematic review and meta-analysis of innovative technologies for 1,2,4-trichlorobenzene remediation in soil and water

The 1,2,4-trichlorobenzene (1,2,4-TCB) is a persistent organic pollutant, which poses a serious concern due to its long-lasting and detrimental impact on soil and water quality. This study uses meta-analysis to investigate the effectiveness of various remediation methods for 1,2,4-TCB in water and soil. In water, the intimate coupling of photocatalysis and biodegradation (ICPB) demonstrated the highest removal rate (80%), followed by photocatalysis (PC, 69%), bioremediation (B, 53%), and photolysis (P, 42%). Optimal conditions for 1,2,4-TCB removal in water included short remediation times (< 5 days), higher temperatures (≥ 25 °C), neutral pH, and specific free radicals (H⁺ > •OH > •O₂⁻). In soil, short-term remediation methods and suspended cultures showed higher removal rates. Topsoil depth layers (≤ 10 cm) exhibited better removal rates than subsoil (> 10 cm). Key factors influencing remediation effectiveness in water were hydraulic retention time (HRT), salinity, and water table depth, while in soil, remediation time and soil depth layer were the most significant. This research highlights the importance of optimizing remediation methods and environmental conditions to remove 1,2,4-TCB from contaminated sites effectively. Further investigation is needed to understand the underlying mechanisms and optimal conditions for these remediation methods, particularly in soil. Effective remediation of 1,2,4-TCB requires a tailored approach considering specific environmental conditions and challenges in water and soil. The ICPB shows promise, especially in aquatic environments. However, further research is essential to optimize these methods, particularly for soil remediation.