Adsorption of Cadmium in Electroplating Wastewater Using Chitosan in Electric Heating Tube Electroplating

Adsorption of Cadmium in Electroplating Wastewater Using Chitosan in Electric Heating Tube Electroplating

Luo Daocheng et al. utilized vanillin modified chitosan (VCG) to treat nickel containing electroplating wastewater from an electroplating plant in Xiangtan ρ The electroplating wastewater with a (Ni2+) concentration of 28.71mg/L and a pH of 6.5 was used. Under experimental conditions, the amount of VCG used was 0.8%, and the wastewater solution met the national discharge standards[ ρ (Ni2+)<2mg/L]。 At the same time, they also studied the influencing factors of VCG on the treatment of simulated electroplating wastewater and the adsorption performance of various metal ions. The study found that at pH=4, θ When the adsorption temperature is 25 ℃ and the shaking adsorption time is 2 hours, the saturated adsorption capacity of heavy metals for 1g/L of Pb2+, Cu2+, Zn2+, Cd2+, and Ni2+solution is 127.3mg/g for Pb2+, 95.6mg/g for Zn2+, 79.4mg/g for Ni2+, 71.8mg/g for Cu2+, and 55.7mg/g for Cd2+. When pH<4, VCG has a smaller adsorption capacity for heavy metal ions, which is not conducive to adsorption; In a neutral solution with a weak acidity of pH ≥ 4, the adsorption capacity of VCG for heavy metal ions greatly increases, which is beneficial for adsorption.

Huang Zengwei et al. used cross-linked chitosan (CCTS) to treat a electroplating plant in Nanning ρ The wastewater with (Cr6+) concentration of 108mg/L was treated, and the experiment found that CCTS had good adsorption characteristics for Cr6+at pH=3, θ When the temperature is 25 ℃, the adsorption time is 80 minutes, and the amount of CCTS is 1g, the removal rate of chromium from electroplating wastewater containing chromium can reach 96%. When the concentration of NaOH solution is 1mol/L and the volume is 5mL, Cr6+can be quantitatively desorbed from CCTS, with a desorption rate of 98%. Wash the eluted CCTS with distilled water until neutral, and dry before reuse. This indicates that CCTS has good regeneration value and has good application prospects in separation, analysis, and water treatment.

Dai Shujuan et al. used chitosan to adsorb cadmium from electroplating wastewater ρ (Cd2+) is 26mg/L, under experimental conditions (pH=5.5 θ Adding 3.3g/L chitosan at 25 ℃ for 10 minutes can achieve a cadmium removal rate of over 96%. The adsorption of cadmium is mainly through chemical complexation, and the main functional groups that play a chemical complexation role are - NH2, - C==O -, - C==O-NH -, - CH3, and - OH. Liu Cunhai et al. used chitosan grafted acrylamide copolymer (CAM) to treat electroplating wastewater with a total chromium content of 10.054g/L from the 5702 Factory of the Chinese People's Liberation Army. The optimal dosage of CAM was determined to be 2mg/L, with a pH of 7.8, a stirring speed of 200r/min, a stirring time of 3min, a settling time of 4h, and a chromium removal rate of 94%.

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