Activated biochar derived from spentAuricularia auriculasubstrate for the efficient adsorption of cationic azo dyes from single and binary adsorptive systems

Abstract

In this study, spent Auricularia auricula substrate (AS)-derived biochar (ASBCs) and activated biochar with NaOH (A-ASBC) were evaluated for the adsorption of cationic azo dyes, including methylene blue (MB), rhodamine B (RB), and crystal violet (CV), from single and binary adsorptive systems. A-ASBC showed a higher maximum adsorption capacity for these dyes (MB: 53.62 mg·g−1, RB: 32.33 mg·g−1, CV: 735.73 mg·g−1) than ASBCs in a single system because it had a greater specific surface area and more oxygen containing-functional groups on the surface. The adsorption process of the three dyes onto the adsorbents was in good agreement with the Freundlich adsorption isotherm and fit the pseudo-second-order kinetic model, which revealed sorbate polymolecular layer formation over the adsorbent surface and the involvement of chemisorption. The adsorption mechanism showed that the adsorption of three dyes on adsorbents could be postulated as a multistep process with extraordinary affinity-induced adsorption in terms of both physisorption and chemisorption. In the binary adsorptive system, the results showed that all MB, RB, and CV had antagonistic/competitive effects on each other's adsorption (QBinary/QSingle < 1). Furthermore, a phytotoxic assay affirmed the effectiveness of the adsorbent in adsorbing dye species from aqueous solutions using Brassica pekinensis L. seeds as the model. Therefore, activated biochar prepared from AS can be used as a potentially economical and effective adsorbent for treating printing and dyeing wastewater.

A new type of calcium-rich biochars derived from spent mushroom substrates and their efficient adsorption properties for cationic dyes

“…As the concentration increased, the adsorption sites tended to be saturated, and eventually adsorption capacity reach equilibrium. For the adsorption of MG and ST, the Freundlich model was more appropriate to describe the actual adsorption process ( Figure 7 a-d, Supplementary Table S3 ), suggesting that the adsorption of two dyes on GSBC and LSBC was nonuniform and multilayered ( Su et al, 2021 ). The 1/ n value were all between 0 and 1, indicative of the favorable adsorption for dyes onto both biochars ( Wang et al, 2018 ).…”

“…By comparing the changes in pH before and after adsorption (Figures 4B,D,F,H), it was found that the final pH increased after dyes adsorption under acidic conditions, the possible reason is that the protonation of functional groups on biochar surface as well as the buffering effect of the inorganic elements in biochar (Su et al, 2021). When in Frontiers in Bioengineering and Biotechnology frontiersin.org alkaline solution, amounts of OH − were combined with the surface functional groups of biochar and involved in dyes adsorption, eventually causing the declined pH.…”

Exploring Modified Rice Straw Biochar as a Sustainable Solution for Simultaneous Cr(VI) and Pb(II) Removal from Wastewater: Characterization, Mechanism Insights, and Application Feasibility

“…Referring to Figure , the rice straw biosorbent follows the type II category. i.e., the adsorbent has both meso- and micropores on the surface . Micropores were observed in the first curve, and the mesopores’ presence was observed in the second curve concerning the relative pressure shown in Figure .…”

Activated Biocarbons Obtained from Plant Biomass as Adsorbents of Heavy Metal Ions

“…Additionally, the ease of their activation and modification allows for the significant development of their porous structure and functionalisation of the surface. Metal ions, synthetic dyes, phenols, amines or pharmaceuticals are commonly adsorbed on the biochars, activated biocarbons (products of physical and chemical activation of biomass) or different kinds of carbon-based nanocomposites [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. These materials are low-cost adsorbents and they can be easily regenerated.…”