Recycling corn stalks as an effective biosorbent for heavy metal removal from wastewater: Investigation on the adsorption performance and mechanism

DETA-functionalized corn stalk cellulose (DCC) biosorbent was successfully prepared from corn stalks and applied to simultaneously remove Cu^2 +, Pb²⁺ and Zn²⁺ from wastewater. Compared with raw corn stalk cellulose, DCC was rich in amino groups and was characterized with larger specific surface area as well as higher chemical polarity. Batch experiments were carried out to optimize the adsorption parameters including the pH value, contact time and initial concentration. The adsorption data followed the pseudo-second-order kinetics model and Langmuir isotherm model better, and the adsorption amount for Cu²⁺, Pb²⁺ and Zn²⁺ in ternary system were 59.10, 68.92 and 60.79 mg/g, respectively. FT-IR and XPS results revealed that the O-containing and N-containing groups on DCC surface played a prominent role in heavy metal adsorption by forming chelating complex with multiligand. Additionally, the DCC biosorbent presented good regeneration performance after 5 cycles. The findings in this paper revealed the DCC biosorbent had promising efficiency in heavy metal removal from effluents, and also offered an alternative strategy to recycle corn stalks for the purpose of ‘waste treatment by waste’.