Adsorption of hexavalent chromium onto Bamboo Charcoal grafted by Cu2+-N-aminopropylsilane complexes: Optimization, kinetic, and isotherm studies

[Display omitted] •Bamboo Charcoal grafted by Cu2+-N-aminopropylsilane complexes (BC/Cu-N) was used as adsorbent.•Removal of wastewater containing Cr(VI) by BC/Cu-N were optimized by RSM.•BC/Cu-N exhibit high adsorption capacity for Cr(VI). The adsorption mechanism of Cr(VI) uptake onto Bamboo Charcoal grafted by Cu2+-N-aminopropylsilane complexes (BC/Cu-N) was investigated. The properties of BC/Cu-N were characterized using XRD, FTIR, SEM, EDS, potentiometric acid–base titration and electrochemical analysis. Results indicated that the framework integrity of BC was kept after modification and the quantity of functional groups on BC/Cu-N surface has changed. There existed functional groups on the BC/Cu-N which could consume OH− and the pHpzc was found to be 6.20. Moreover, electrochemical analysis showed that new electron transfer pathway was imported. Parameters such as pH, initial Cr(VI) concentration, adsorbent dosage and temperature were optimized using RSM. Analysis of variance of the quadratic model for Cr(VI) was suitable to predict the adsorption of Cr(VI) (F value=134.23 and P value