Synthesis of Cost-Effective Pomelo Peel Dimethoxydiphenylsilane-Derived Materials for Pyrene Adsorption: From Surface Properties to Adsorption Mechanisms

This study investigated the adsorption behaviors of pyrene (PYR) on a pomelo peel adsorbent (PPA), biochar (PPB), and H 3 PO 4 -modified (HPP), NaOH-activated (NPP), and dimethoxydiphenylsilane-treated (DPDMS-NPP) pomelo peel materials. SEM, FTIR, and elemental analyses of DPDMS-NPP's surface structure showed that the material was characterized by a well-developed porous structure, a large specific surface area (698.52 m 2 g -1 ), and an abundance of phenyl functional groups. These properties enhance the PYR adsorption performance of DPDMS-NPP. Experimental results indicated that the adsorption capacity of DPDMS-NPP was significantly affected by the amount of material used and the initial concentration of PYR. Kinetic assessments suggested that PYR adsorption on PPA, NPP, and DPDMS-NPP could be accurately described by the pseudo second-order model. The adsorption process was controlled by several mechanisms, including electron donor-acceptor (EDA), electrostatic, and π-π interactions as well as film and intraparticle diffusion. The adsorption isotherm studies showed that PYR adsorption on DPDMS-NPP and PPA was well described by the Langmuir model and the maximum Langmuir adsorption capacity of DPDMS-NPP was 531.9 μg g -1 . Overall, the results presented herein suggested that the use of DPDMS-NPP adsorbents constitutes an economic and environmentally friendly approach for the mitigation of PYR contamination risks.