Adsorptive removal of cationic methylene blue and anionic Congo red dyes using wet-torrefied microalgal biochar: Equilibrium, kinetic and mechanism modeling

Biochar as an Eco-Friendly and Economical Adsorbent for the Removal of Colorants (Dyes) from Aqueous Environment: A Review

“…The removal percentage of dye increased significantly for a very small increase in adsorbent (<1 g/100 mL) in all of the above-mentioned studies. This was similar to another study [102], which concluded that the increase in percentage of dye removal was because of the increase in dosage of adsorbent, which in turn increased the active sites for adsorption as well the surface area of adsorbent. However, the percentage of dye removal remained constant after a certain dosage of biochar due to the decrease in amount of dye molecules adsorbed per unit mass of adsorbent and the decrease in specific uptake [99].…”

“…The dosage of adsorbent as well as adsorbate influence the extent of adsorption of dye and are important parameters to be considered. In a study of adsorption of dye using biochar [102], the removal percentage and capacity of adsorption were influenced heavily by the dosage of adsorbent. Even for a small increase in dosage of adsorbent caused the removal percentage to increase significantly (almost an 80 percent increase) and remained constant after a certain maximum dosage was reached.…”

“…Even for a small increase in dosage of adsorbent caused the removal percentage to increase significantly (almost an 80 percent increase) and remained constant after a certain maximum dosage was reached. This phenomenon, according to authors [102], was due to the fact that at higher dosages of adsorbent, the number of active sites, as well as surface area of adsorption, will increase drastically, which in turn will increase the removal percentages of the dye present in water. A similar increase in percentage of dye removal with increase in adsorbent dosage was also observed in other studies [99,103,104].…”

Characterization and Adsorption Applications of Composite Biochars of Clay Minerals and Biomass

“…Previous studies have suggested that if qt vs. t1/2 was a straight line and the plot passes through the origin, then intra-particle diffusion is the rate-limiting step in the adsorption process. Otherwise, the adsorption process is controlled by multiple steps (Hameed et al, 2008b;Jang et al, 2018;Kai Ling Yu, Xin Jiat Lee, Hwai Chyuan Ong, Wei-Hsin Chen, Jo-Shu Chang, Chih-Sheng Lin, Pau Loke Show, 2020). As shown in Fig 4(b), the qt vs. t1/2 was fitted by three straight line.…”

Dual functioning TiO₂-brilliant yellow composite for efficient removal of methylene blue from water

“…However, degradation of some of the synthetic dyes is challenging due to their high stability under light and oxidation processes (Sing, 1998). Adsorption technique is widely practiced for removal of dyes which are resistant for degradation and due to its high efficiency, comparatively low cost, reusability and facile regeneration of the adsorbent (K. Ramakrishnan et al, 2021;Yu et al, 2021). Porous materials such as alginate beads, activated carbons, zeolites, metal organic frameworks, polymeric resins, metal matrix composites and clays are some of the examples for materials used in adsorptive removal (Haque et al, 2011).…”