Adsorption Characteristics of Chitosan-Modified Bamboo Biochar in Cd(II) Contaminated Water

Abstract

The purpose of this study was to fabricate a low-cost and eco-friendly adsorbent using bamboo biochar (BB), a kind of charcoal composed of high Brunauer–Emmett–Teller surface area and variety of functional groups, and chitosan as substrates for remediation of Cd(II) in Cd(II) contaminated water and characterized the functional group characteristics, surface morphology, and Cd(II) adsorption effect using the Fourier transform infrared (FT-IR), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometer (EDS). Results showed that chitosan-modified bamboo biochar (CBB) provided more active adsorption sites (such as –NH2, –COOH, –OH, and C=O) on the surface to enhance the Cd(II) removal efficiency in Cd(II) contaminated wastewater. Meanwhile, the optimal pH, contact time, and dose of CBB on the Cd(II) removal efficiency are 7, 120 min, and 600 mg, respectively. In addition, the adsorption isotherm results revealed that the possible adsorption mechanisms might include surface adsorption, electrostatic adsorption, and ion exchanges. Furthermore, the maximum adsorption capacity (Qm) values predicted from the Langmuir model were 37.74 and 93.46 mg/g for BB and CBB, respectively, also indicating a potential application of CBB in practical wastewater. Desorption and regeneration of CBB were attained simultaneously and the results showed that even after five cycles of adsorption-elution, the adsorption and desorption of CBB exhibited a slight decline and still reached at 71.70% and 65.92%. Results from this study would provide a reference to functionalized CBB for Cd(II) adsorption in contaminated water.

Chitosan-Modified Biochar and Unmodified Biochar for Methyl Orange: Adsorption Characteristics and Mechanism Exploration

“…The external morphology of CSBC generally possesses a highly irregular surface compared to the well-defined cylindrical pores of the RHB surface. These results were similar to other observations [40,54]. The SEM morphological structures of CSBC and RHB are shown in Figure 4A.…”

“…For example, chitosan-coated onto biochar surfaces showed an adsorption capacity for phloridzin (28.96 mg.g −1 ), nearly double the unmodified biochar derived from apple branches (15.93 mg.g −1 ) [39]. Additionally, the modification of chitosan on biochar surface has been shown to have greater adsorption capacities for Cd(II) and Pb(II) ions than unmodified biochar [40,41].…”

Preparing Shrimp Shell-Derived Chitosan with Rice Husk-Derived Biochar for Efficient Safranin O Removal from Aqueous Solution

“…4B) had an irregular surface, which might be due to the incorporation of chitosan in the biochar surface. Therefore, these SEM results showed that the biochar surface could be covered by the chitosan, and even the biochar pores could be penetrated by the chitosan, thereafter the porosity structure of biochar surface was altered, similar to other observations (Ahmed et al 2016;Huang et al 2022).…”

“…Below these pH pzc , the CS@BC and BC surface charges are positive, while above pH pzc their surfaces are negative. Therefore, the chitosan loaded on the biochar derived from rice husk increased the positive charge, and these findings were similar to the chitosan loaded on the biochar derived from bamboo (Huang et al 2022).…”

“…Several studies also reported similar enhanced findings. For example, CS@BC exhibited nearly twice more phloridzin sorption than the BC produced from apple branches at 300 °C (Ma et al 2021); nearly 2.5 times more Cd(II) sorption than the BC produced from bamboo at 900 °C (Huang et al 2022), and nearly 3 times more Pb(II) sorption than the BC produced from pine wood at 425 °C (Dewage et al 2018).…”