超声波改性玉米秸秆对Cr(Ⅵ)吸附性能的探究

Studies on adsorption of Cr(Ⅵ) in water by ultrasonic modified corn straw

本文利用超声波对玉米秸秆进行改性制备改性玉米秸秆吸附剂,考察了改性过程中时间以及温度对制备玉米秸秆吸附剂的影响。试验表明,超声波改性的玉米秸秆对Cr(Ⅵ)具有很好的吸附性能。试验结果还表明:吸附剂用量为0.8g/50 mL、溶液初始浓度为20 mg/g、pH值为2.0、温度为45℃、吸附时间为2.5 h时,吸附剂对Cr(Ⅵ)的吸附率可以达到98%以上。此外,通过吸附动力学和热力学实验研究表明,超声波改性的玉米秸秆对Cr(Ⅵ)的吸附机理更符合准二级动力学模型和朗格缪尔模型,且吸附过程是自发吸热进行的。该研究结果可为吸附重金属废水提供参考。

In this paper,the modified corn straw adsorbent was prepared by ultrasonic modification of corn straw;the effects of time and temperature during the modification process on the preparation of corn straw adsorbent were investigated.The experimental results showed that the best modification effect of corn straw was achieved by ultrasonic for 5 minutes at 40 ℃.The modified corn straw was used as the adsorbent to adsorb the Cr(Ⅵ) in the solution,and the effects on the adsorption behavior of Cr(Ⅵ) were studied from the aspects of adsorbent dosage,initial Cr(Ⅵ) concentration,pH value,temperature and time.The experimental results showed that when the amount of adsorbent was 0.8 g/50 mL,the initial concentration of solution was 20 mg/g,the pH value was 2.0,the temperature was 45 ℃,and the adsorption time was 2.5 h,the adsorption rate of Cr(Ⅵ) to adsorbent could reach over 98%.Adsorption kinetics study and adsorption thermodynamics showed that,the adsorption mechanism of Cr(Ⅵ) more in line with the Langmuir isotherm model and quasi-second-order kinetic model,and the adsorption process was spontaneously endothermic.The results can provide references for the adsorption of heavy metal containing wastewater.