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

•Increase in the sorption capacity of up to 21.6 times of AW@APTES-0.5 to AW.•AW@APTES-0.5 was used for the treatment of textile wastewaters with the removal of 98.66%.•AW presented an overall removal of only 10.24% of the textile wastewater.•Studies indicate that the mechanism of adsorption of RB-4 onto AW@APTES-0.5 was mainly electrostatic attraction at pH 2. Biomass-based materials present low sorption capacity. In order to overcome this disadvantage, chemical modification of these materials is required. 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 AW@APTES-0.25, AW@APTES-0.50, AW@APTES-1.0, AW@APTES-1.5, and AW@APTES-2.0, that were characterized by hydrophobic/hydrophilic balance, CHN elemental analysis, surface area, TGA, FTIR, and pHpzc. For screening purposes, the five materials were tested as adsorbents to remove reactive blue 4 (RB-4) from water. The results showed that AW@APTES-0.5 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 AW@APTES-0.5 (50 °C). An increase in the Qmax value of AW@APTES-0.5 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. [Display omitted]