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| Kinetic and thermodynamic characteristics of phosphorus adsorption by modified corn straw |
| Received:March 20, 2020 |
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| KeyWord:modified corn straw;phosphorus;isothermal adsorption;adsorption mechanism |
| Author Name | Affiliation | E-mail | | HAN Jue | Green Intelligence Environmental School, Yangtze Normal University, Chongqing 408100, China
School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China | | | LI Jia-xin | School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China | | | CUI Hong-yan | School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China | | | Lü Wei | School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China | | | BAI Shu-qin | Green Intelligence Environmental School, Yangtze Normal University, Chongqing 408100, China
School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China | baishuqin2000@163.com |
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| Abstract: |
| In order to realize the resource utilization of corn straw, this study used corn stalks as raw materials after a series of chemical modifications including hydrolysis with NaOH solution, ultrasonic vibration, epichlorohydrin etherification, and Ca(NO3)2 soaking. The corn residues were modified into cationic adsorbents, and the adsorption of phosphorus in water was studied. The influences of the initial concentration of phosphorus solution, adsorption time, and adsorption temperature on the adsorption of phosphorus were observed. The results indicated that the adsorption amount began to increase sharply with the increase in reaction time, and then slowly decreased to reach equilibrium. The equilibrium adsorption capacity of phosphorus increased with the increase in initial concentration. The adsorption process of phosphorus by modified corn straw was well-fitted to a Langmuir adsorption isotherm when the temperature was 298 K, and the maximum adsorption of phosphorus was 12.96 mg·g-1. The study of the adsorption kinetics showed that it was also well-fitted to the pattern of the pseudo second-order model and controlled by the pattern of the particle diffusion model, thereby indicating that the adsorption process was dominated by chemical adsorption. Thermodynamic experiments with varying adsorption temperatures showed that the thermodynamic parameters ΔH and ΔG were less than zero, which revealed that the adsorption process was exothermic and spontaneous. The results showed that the modified corn stalk has a good removal effect on phosphorus in water and is a good adsorbent of phosphorus. |
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