Review on utilization of biochar for metal-contaminated soil and sediment remediation

Thallium contamination in agricultural soils and associated potential remediation via biochar utilization

“…Specifically, biochar plays a prominent function in limiting Tl leachability and other natural pollution in soils at some point in the adsorption technique. Due to the sufficient pore shape of biochar, Tl can migrate from the outer sphere to the internal sphere of the adsorbent (Wang et al 2018a, b) because it contains a significant number of sorption houses primarily based on its negative surface charge, bulk density, and surface area (Ali et al 2019). For example, the abundance of negatively charged surface sites on biochars because of the presence of functional groups such as carboxyl, hydroxyl, and phenolic (-COO − and -OH − ) can bind Tl cationic as a toxic metal and thereby decrease its mobility in soil (Shaheen et al 2019).…”

Contaminated Sediments

“…Several mineral-based materials have been studied for their ability to remediate metal-contaminated soil and sediment. These include zero-valent iron, hematite, ferrihydrite, apatite and clays (Qian, Chen et al 2009, Su, Fang et al 2016, Wang, Zhu et al 2017. The natural calcium-rich clay minerals sepiolite and attapulgite can effectively reduce both the mobile metal fraction and the bioavailability to benthic organisms in Pb and Cd polluted sediments (Yin and Zhu 2016).…”

“…Biochar is a carbon-neutral or carbon-negative material produced through thermal decomposition of plant-and animal-based biomass under oxygen-limited conditions (International Biochar Initiative, 2012). Biochar has been successfully used to reduce metal bioavailability in soil and resulting metal concentration in rice (Wang et al 2018) and it is suggested that biochar could also be a suitable option for in situ capping for remediation of metal contaminated sediments (Wang, Zhu et al 2017). Biochars derived from different biomass sources have different properties (Wang, Zhu et al 2017), potentially making it possible to choose the most efficient biochar for the specific sediment contamination to be remediate.…”

“…Biochar has been successfully used to reduce metal bioavailability in soil and resulting metal concentration in rice (Wang et al 2018) and it is suggested that biochar could also be a suitable option for in situ capping for remediation of metal contaminated sediments (Wang, Zhu et al 2017). Biochars derived from different biomass sources have different properties (Wang, Zhu et al 2017), potentially making it possible to choose the most efficient biochar for the specific sediment contamination to be remediate. So far (to the best of our knowledge) no studies applying biochar as an active cap to remediate contaminated sediments have been performed.…”

“…So far (to the best of our knowledge) no studies applying biochar as an active cap to remediate contaminated sediments have been performed. A conceptual model for use of biochar and in combination with other materials to reduce risk of metal pollutants for environmental systems was presented by Wang et al (2017).…”