江蓠藻渣及其膳食纤维对Pb^(2+)和Cd^(2+)吸附研究

Studies on the Pb^(2+) and Cd^(2+) adoption of gracilaria residue and its dietary fiber

江蓠提取琼胶后的藻渣如直接废弃将污染环境。江蓠藻渣中富含纤维素、半纤维素和木质素,利用废弃的藻渣提取膳食纤维进行高值化利用,不但可以解决环境污染问题,还可以变废为宝。本文研究了江蓠藻渣及其膳食纤维对Pb2+、Cd2+的吸附作用,探讨了pH值、温度、吸附时间、金属离子初始浓度等因素对其吸附性能的影响。研究表明:藻渣粉末和经过酶法活化的膳食纤维在pH=7时对Pb2+、Cd2+的吸附能力最强,吸附容量随着Pb2+、Cd2+初始金属离子浓度的增大而增大。藻渣粉末和经过酶法活化的膳食纤维对Pb2+、Cd2+的吸附动力学和热力学分别符合Lagergren方程二级吸附模型和Langmu ir吸附方程;单一金属溶液中藻渣粉末和经过酶法活化的膳食纤维对Pb2+的吸附量大于Cd2+,当金属离子浓度为500 mg/L时,藻渣对Pb2+和Cd2+吸附量分别为:19.12 mg/g和12.25 mg/g;膳食纤维对Pb2+和Cd2+吸附量分别为:21.93 mg/g和12.63 mg/g。

The gracilaria residue from agar processing which is rich in cellulose,hemicelluloses and lignin will cause environmental pollution if it is directly abandoned.Extracting dietary fiber from the residue and its utilization of high value can not only prevent environmental pollution,but also make the residue become the valued resource.In this article,the Pb2＋and Cd2＋ adoption of gracilaria residue and its dietary fiber was studied to determined the effect of pH value,temperature,reaction time and initial ions concentration on the properties of adoption.The result shows that gracilaria residue and its dietary fiber have the highest Cd2＋ and Pb2＋ absorption rate at pH=7,and absorption rate decrease with the increase of concentrations of initial metals ions.The adsorption kinetics and adsorption thermodynamics accord with secondary adsorption model of Lagergren equation and Langmuir adsorption equation.In single metal ion solution,the Pb2＋ adsorption is much stronger than Cd2＋.At 500 mg/L ions concentration,the Pb2＋ adsorption of the residue and its dietary fiber are 19.12 mg/g and 21.93 mg/g respectively,and Cd2＋ are 12.25 mg/g and 12.63 mg/g respectively.