Fast and efficient adsorptive capture of Congo red and Erythromycin pollutants by a novel nanobiosorbent from crosslinked nanosilica with nanobiochar and chitosan

Dyes and pharmaceuticals in wastewater are categorized as serious hazardous pollutants due to their nonbiodegradability and therefore, must be removed before discharge in water resources. In this work, a novel nanobiosorbent was fabricated via microwave crosslinking of nanosilica gel with banana peels nanobiochar (BPNB) and chitosan hydrogel (Chit Hgel) to produce BPNB-NSiO2-Chit Hgel nanobiosorbent (22.48-26.23 nm). The effects of nanobiosorbent dosage (1–50 mg), pH (2–12), shaking time (1– 45 min), pollutant concentration (5–100 mg L-1), temperature (288–333 K), and interfering salts on the adsorption of Erythromycin antibiotic (ERM) and Congo red dye (CRD) pollutants were investigated and optimized. Pseudo-second-order model revealed a perfect fitting to the experimental data, while Langmuir model achieved (R2 = 0.997 for ERM and R2 = 0.992 for CRD) as the highest correlation coefficients. Moreover, adsorptive capture reactions of ERM and CRD onto BPNB-NSiO2-Chit Hgel were classified as spontaneous and endothermic. The removal of ERM (92.80–96.50%) and CRD (92.80–95.0%) from tap, sea, and wastewater was successfully established to confirm the validity and capability of the investigated BPNB-NSiO2-Chit Hgel nanobiosorbent in removal of these two pollutants from polluted water samples.