Synthesis and characterization of Biochar-Doped Chitosan Aerogels for enhanced heavy metal adsorption in wastewater treatment

This study reports the synthesis and characterization of citric acid-crosslinked chitosan aerogels doped with biochar derived from Hass avocado seeds (HH) and cocoa husks (HCH) for the adsorption of hexavalent chromium (Cr(VI)) from aqueous solutions. Hydrochars were produced via hydrothermal carbonization with phosphoric acid activation and characterized by FTIR-ATR, thermogravimetric analysis (TGA), and Boehm titration. HH exhibited a higher yield (58.76%) and greater phenolic and basic group content, favoring chemisorption and redox reduction of Cr(VI), while HCH presented a more acidic surface profile. Nine aerogel formulations were synthesized using an in-situ doping strategy. FTIR confirmed citric acid ester crosslinking and the contribution of HH aromatic/carboxylate groups. TGA revealed enhanced thermal stability in mid biochar–citric acid formulations, particularly in 4-CHAC-5, which exhibited the highest Cr(VI) removal (95.72%) and adsorption capacity (23.93 mg/g). Adsorption studies showed pseudo-second-order kinetics and Langmuir-type monolayer adsorption with a maximum capacity of 64.52 mg/g. The results demonstrate that HH biochar–doped chitosan aerogels are promising, sustainable adsorbents for heavy metal removal in wastewater treatment.

• Egile nagusia: Maza Agurto, Karol Dayanna (author)
• Formatua: bachelorThesis
• Argitaratua: 2026
• Gaiak: Aerogel de quitosano; Biocarbón; Ácido Cítrico; Chitosan aerogel; Biochar; Citric acid
• Sarrera elektronikoa: https://repositorio.yachaytech.edu.ec/handle/123456789/1046