Journal of Ecology and Rural Environment ›› 2020, Vol. 36 ›› Issue (11): 1468-1476.doi: 10.19741/j.issn.1673-4831.2020.0130

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Adsorption Characteristics of Cd2+ and Pb2+ in Wastewater by 4 Agricultural Wastes

YANG Lan-qing1, ZHANG Shi-rong1,2, PENG Ya-xi1, WANG Gui-yin1,2, XU Xiao-xun1,2   

  1. 1. College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China;
    2. Sichuan Provincial Key Laboratory of Soil Environmental Protection, Chengdu 611130, China
  • Received:2020-02-28 Online:2020-11-25 Published:2020-11-18

Abstract: In order to discuss the adsorption characteristics of different agricultural wastes on Cd2+ and Pb2+ in wastewater, the powder of peanut straw (HG), sunflower faceplate (KP), cotton husk (MK) and cotton straw (MG) were selected for the study. The studied adsorption characteristics include dosage, solution pH, adsorption time, initial solution concentration and ionic strength. The results show that the adsorption capacities of Cd2+ and Pb2+ by the peanut straw, sunflower faceplate and cotton husk decreased exponentially or logarithmically when the dosage increased from 0.025 g to 0.200 g (P<0.05). With the increasing pH, the adsorption capacities of Cd2+ and Pb2+increased initially and then remain unchanged. Those of peanut straw and cotton husk are significantly higher than the other two materials (P<0.05). The sorption kinetics of Cd2+ and Pb2+ on the four materials follows the pseudo-second order model. Isothermal adsorption of Cd2+ and Pb2+ by HG, KP, and MK fitted well with Langmuir equation, while Freundlich equation is more suitable for the MG. The maximum adsorption capacity of the four materials on Cd2+ and Pb2+ was 59.18-93.13 mg·g-1 and 106.43-167.73 mg·g-1, respecrtively. The existence of Na+ can significantly reduce the adsorption capacities on Cd2+ by the four materials and on Pb2+ by cotton straw (P<0.05).

Key words: cadmium, lead, adsorption, peanut straw, sunflower faceplate, cotton husk, cotton straw

CLC Number: