WITHDRAWN: Study on Adsorption Properties of Loess Calcareous Nodules to Heavy Metalions In Aqueous-solution

Abstract Using calcareous calcareous tuberculosis as adsorbent and heavy metal ions (Cu 2+ , Zn 2+ , Cd 2+ and Pb 2+ ) as adsorbents, different particle size, adsorption time, pH, adsorbent dosage and initial concentration of heavy metals were studied by single heavy metal adsorption test. And the influence of temperature and other factors on the adsorption of heavy metal ions by calcareous nodules, and determine the optimal conditions for the adsorption of heavy metal ions by calcareous nodules. The results show that the adsorption rates of Cu 2+ , Zn 2+ and Pb 2+ decrease gradually with the increase of particle size, but have no obvious effect on Cd 2+ . With the increase of adsorption time, adsorbent dosage and temperature, the adsorption rates of Cu 2+ , Zn 2+ , Cd 2+ and Pb 2+ gradually increase. The adsorption rate of Cu 2+ , Zn 2+ and Cd 2+ decreased gradually with the increase of the initial concentration of heavy metal ions, while the adsorption rate of Pb 2+ increased first and then decreased. With the increase of pH, the adsorption rate of Cd 2+ increased first and then increased slowly. The adsorption rates of Cu 2+ , Zn 2+ and Pb 2+ increased first and then decreased. The adsorption capacity of calcareous nodules to four heavy metal ions is in the order of Pb 2+ ＞Zn 2+ ＞Cu 2+ ＞Cd 2+ . When the particle size is 0.25 mm, the adsorption time is 120 min, and the dosage is 0.6 g, the calcareous nodules are Pb 2+ , Zn 2+ , Cu 2+ . And Cd 2+ can achieve better adsorption, and the adsorption rate can reach 83.33%, 77.78%, 73.81% and 81.93% of its maximum adsorption rate, respectively. The optimal adsorption pH of calcareous nodules to Pb 2+ , Zn 2+ , Cu 2+ and Cd 2+ was 7, 6, 5 and 8, respectively, and the optimal temperature was 50 °C.