Advanced clay sorbents have attracted widespread attentions for applications in environment remediation and pollution control. Here, a facile and environmentally-friendly approach to synthesizing a porous Na-bentonite/ hickory-biochar composite sorbent from hickory waste biomass using hand-milling and carbon-bed pyrolysis was investigated. The sorbents, made using a range of clay/biomass ratios and at a range of temperatures, were characterized and examined for their ability to remove Eriochrome blue black R (EBBR) anionic organic dyes from aqueous solution. The composite sorbents showed increased microporosity and O-containing functional groups over the pyrolyzed bentonite control. The composite prepared with 10% biomass by weight, and at 600 degrees C had the greatest EBBR adsorption, and was best fit to Freundlich isotherm and intraparticle diffusion kinetics models. The modeled maximum EBBR sorption capacity of this composite (2020.5 mg g-1, R2 adj = 0.92), which was attributed to the dispersion of bentonite particles over the biochar surface. These results show the bentonite/ biochar composite to have great potential for use in environmental remediation applications.

Advanced biosorbents increasingly attract attention for their application in environment remediation. Here, a facile one-step approach to alkaline ball milling was used to synthesize a porous peanut hull biosorbent without heating. The alkaline ball-milled peanut-hull (ABP) biosorbent was characterized for its ability to remove Congo red (CR), titan yellow (TY), and methyl violet (MV) from aqueous solutions. ABP processed abundant O -con-taining functional groups and developed porosity, resulting in maximum sorption capacities of 4864.4 (CR), 455.9 (TY), and 126.1 (MV) mg g-1. Freundlich isotherm and PSO kinetic models best fit the anionic dye's (CR and TY) adsorption by ABP, indicating multiple mechanisms might control the adsorption process. Freundlich and PFO kinetics models best described cationic MV adsorption by ABP, suggesting the adsorption of cationic dye could also be governed by multi-mechanisms but less heterogeneous than that of anionic dye. The results suggest that alkaline ball-milling is promising approach to converting biomass into advanced biosorbents for organic dyes, especially anionic ones.

New classes of biosorbents are needed for various environment remediation applications. Thus, a facile and benign approach to synthesize porous biosorbents was developed using acidic or alkaline one-step ball milling of hickory wood biomass (AcBH and AlBH, respectively) without any external heat treatment, and their properties were compared. AcBH and AlBH were richer in O-containing functional groups, had enhanced porous structure and greater ability to remove crystal violet (CV, 476.4 mg g-1) and Congo red (CR, 221.8 mg g-1) dyes from aqueous solution, respectively, relative to hickory wood ball milled at neutral pH. Freundlich isotherm and pseudo second order kinetic models best fitted CR and CV adsorption onto biosorbents, indicating a mainly surface complexation adsorption mechanism. Further, both sorbents exhibited excellent stability and dye adsorption reusability. These results demonstrate that acidic and alkaline one-step ball milling is a facile and efficient approach for converting wood biomass into environmentally friendly biosorbents.