核桃果皮炭粉对3种重金属离子吸附的影响

Study on influencing factors of adsorption of three heavy metals by carbonized powder of walnut peel

采用均匀设计的实验方法,研究了2种核桃果皮炭粉(提取水溶性混合物和未提取水溶性混合物的核桃皮炭粉)对Cr、Cu和Cd等重金属离子的吸附最优条件以及对3种离子吸附的影响因素。结果表明,核桃皮炭粉对Cr(Ⅵ)、Cd2+和Cu2+的吸附最优条件为:pH=4,温度为60℃,浓度为150μg/mL,吸附剂用量为2.4 g,时间为120 min;pH=4.5,温度为30℃,浓度为180μg/mL,吸附剂用量为5.4 g,时间为60 min;pH=5,温度为80℃,浓度为210μg/mL,吸附剂用量为0.4 g,时间为100 min;pH和Cr(Ⅵ)浓度增大,不利于2种吸附剂对Cr(Ⅵ)的吸附;pH和温度增大,不利于2种吸附剂对Cu2+的吸附;温度和吸附剂用量增加,有利于2种吸附剂对Cd2+的吸附。未提取水溶性混合物比提取水溶性混合物的核桃果皮炭粉对3种金属的吸附显著。2种吸附剂的吸附率均表现为Cr>Cd>Cu。

In this study,uniform design method was applied for the optimization of adsorption conditions of three heavy metals by carbonized powder of walnut peel( CPWP). The optimal conditions of adsorbing Cr( Ⅵ),Cu and Cd by two CPWPs( water-soluble component were extracted out and not extracted out) and the factors of influencing adsorption were studied. The results showed that the optimal conditions of adsorbing Cr( Ⅵ),Cu and Cd were pH of 4,temperature of 60℃,Cr( Ⅵ) ion concentration of 150 μg /mL,adsorbent dosage of 2. 4 g,time of 120 min; pH of 7,temperature of 30℃,Cu2 +concentration of 180 μg /mL,adsorbent dosage of 5. 4 g,time of60 min; pH of 5,temperature of 80℃,Cd2 +concentration of 210 μg /mL,adsorbent dosage of 0. 4 g,time of 100 min,respectively. With the increasing of pH and the concentration of Cr( Ⅵ),the adsorption of Cr( Ⅵ) by both adsorbents decreased. With the increasing of pH and temperature,the adsorption of Cu2 +decreased. However,the increasing of temperature and the amount of adsorbents led to the increased adsorption of Cd2 +by both adsorbents. In addition,the CPWP which water-soluble component was not extracted out had better adsorption activity than the CPWP which water-soluble component was extracted out for three metal ions. The adsorptive rates of both adsorbents presented as Cr > Cd > Cu.