Microalgal-based biochar in wastewater remediation: Its synthesis, characterization and applications

Microalgae are drawing attentions among researchers for their biorefinery use or value-added products. The high production rate of biomasses produced are attractive for conversion into volatile biochar. Torrefaction, pyrolysis and hydrothermal carbonization are the recommended thermochemical conversion techniques that could produce microalgal-based biochar with desirable physiochemical properties such as high surface area and pore volume, abundant surface functional groups, as well as functionality such as high adsorption capacity. The characterizations of the biochar significantly influence the mechanisms in adsorption of pollutants from wastewaters. Specific adsorption of the organic and inorganic pollutants from the effluent are reviewed to examine the adsorption capacity and efficiency of biochar derived from different microalgae species. Last but not least, future remarks over the challenges and improvements are discussed accordingly. Overall, this review would discuss the synthesis, characterization and application of the microalgal-based biochar in wastewater.

Automated summary

Microalgae are attracting attention for their potential biorefinery use or value-added products, with their biomass being converted into volatile biochar through recommended thermochemical conversion techniques. The resulting biochar has desirable properties such as high surface area and pore volume, abundant surface functional groups, and high adsorption capacity. The characteristics of biochar significantly influence the adsorption mechanisms of pollutants from wastewaters, with specific adsorption of organic and inorganic pollutants being reviewed in terms of capacity and efficiency. Future challenges and improvements in the application of microalgal-based biochar in wastewater treatment are also discussed.