Comparative and competitive adsorption of gaseous toluene, ethylbenzene, and xylene onto natural cellulose-modified Fe3O4 nanoparticles

Abstract

Many industrial processes produce volatile organic compound (VOC) pollutants within multicomponent systems. Therefore, exploring the comparative and competitive adsorption of VOCs is of both practical and scientific interest. This study elucidates the adsorption behavior of gaseous toluene, ethylbenzene, and xylene (TEX) targeted as VOCs onto natural cellulose-modified Fe3O4 (NC-Fe3O4) nanoparticles (NPs) both individually and in multicomponent systems for the first time in the literature. The characterization of NC-Fe3O4 synthesized via co precipitation method was carried out with analysis techniques including BET, SEM, EDS, FTIR, and TGA-DTA. The adsorption capacities of TEX as a single-component onto NC-Fe3O4 (for 20 mg L-1 TEX inlet concentration) were found as 477, 550, and 578 mg g(-1), respectively. In contrast, with TEX in a binary-component system, the adsorption capacity of the T (for 20 mg L-1 T with 10 mg L-1 E and 10 mg L-1 X, respectively) decreased by approximately 43% and 50% for the binary-mixtures of T-E and T-X, respectively, due to competition with E and X for adsorption sites. Similarly, the adsorption capacity of the E (for 20 mg L-1 E with 10 mg L-1 X) decreased by approximately 46% due to competition with the X for adsorption sites. With TEX in a ternary-component system, the adsorption capacity of the X remained consistent, indicating its competitive dominance over the E and T. The adsorption capacity of NC-Fe3O4 followed the order of X > E > T in the ternary-component system, which agrees with the adsorption results for the single-component system. The adsorption mechanism of TEX was explained by fitting the adsorption data to diverse kinetic and isotherm models. The NC-Fe3O4 with a superior performance in terms of both reuse efficiency and adsorption capacity, could be used as a promising and renewable adsorbent for efficient treatment of VOC pollutants. The findings of the current study will contribute to a better understanding of the comparative and competitive adsorption behaviors among different VOC pollutants in relation to a given adsorbent.