Carboxylate modification of sugarcane bagasse for effectively Cd(II) removal from aqueous solutions: a low-cost renewable and environment-friendly agricultural waste-based adsorbent

作者：Ma, Jinzhen; Li, Ping^*; Wang, Su-nv; Zheng, Xiangyu; Wu, Jinhua

来源：Desalination and Water Treatment, 2021, 224: 243-255.

DOI：10.5004/dwt.2021.27130

• Cd(II)
• Adsorption
• Carboxymethylation
• Regeneration
• Sugarcane bagasse

The toxic Cd(II) in aqueous solution is a poisonous ion and attracts much attention recently. Based on the conception of "treating waste with waste," carboxylate-functionalized sugarcane bagasse (CF-SCB) was successfully fabricated via a facile carboxymethylation process to absorb cadmium in wastewater as a low-cost and environment-friendly material. The chemical structure of CF-SCB were confirmed by scanning electron microscopy, energy dispersive X-ray, and Fourier-transform infrared, respectively. The influences of solution pH, adsorbent dosage, ionic strength, contact time, and the initial concentration of Cd(II) on the adsorption capacities were investigated in detail. The Cd(II) adsorption capacity of CF-SCB increased more than 10 times of pH 6 when the raw SCB was used as the control. The experimental adsorption data were best described by pseudo-second-order kinetic model and Langmuir isotherm with a maximum adsorption capacity of 134.23 +/- 5.68 mg/g at pH 6 and 120.19 +/- 4.28 mg/g at pH 4. Five-cycle reusability tests proved CF-SCB exhibited good reusability with a slight adsorption capacity loss (<11.6%). All the results revealed that the primary mechanism of Cd(II) adsorption was the ion exchange. This study paved a facile method to fabricate a cost-effective adsorbent CF-SCB, which presented excellent adsorption capability and reusability, which could be an enormous potential candidate for remediating wastewater polluted by cadmium ion.