Preparation of hybrids of wood sawdust with 3-aminopropyl-triethoxysilane. Application as an adsorbent to remove Reactive Blue 4 dye from wastewater effluents

Background: Biomass-based materials present low sorption capacity. In order to overcome this disadvantage, chemical modification of these materials is required. Methods: Hybrids of biomass-based materials were obtained by reacting (25%-200% weight) 3-aminopropyl-triethoxysilane (APTES) with the biomass Ayous wood sawdust (AW), obtaining the hybrid materials [email protected], [email protected], [email protected], [email protected], and [email protected], that were characterized by hydrophobic/hydrophilic balance, CHN elemental analysis, surface area, TGA, FTIR, and pH_pzc. Significant findings: For screening purposes, the five materials were tested as adsorbents to remove reactive blue 4 (RB-4) from water. The results showed that [email protected] attained the maximum removal of RB-4. The kinetics and equilibrium data were suitably fitted by the nonlinear General-order kinetic (GO) and Liu equilibrium adsorption models. The maximum amount adsorbed of RB-4 dye was 415.1 mg g ^{− 1} using [email protected] (50 °C). An increase in the Q_max value of [email protected] concerning unmodified AW attained up to 21.6 times. The ΔG° and ΔH° indicated that the adsorption processes of RB-4 onto adsorbents are endothermic and spontaneous, and the magnitude of enthalpy of adsorption (25.10 kJ mol⁻¹) is compatible with the electrostatic attraction mechanism. The adsorbents’ applicability for treating simulated dye effluents showed an excellent efficiency attaining 98.66% removal of the effluent.