激光粒度仪测定纳米腐殖酸粒度的实验研究

Experimental determination of particle size of nanoscale humic acid by laser particle size analyzer

利用激光粒度分析仪考察了分散剂种类及浓度、超声温度、超声时间、纳米腐殖酸浓度等对纳米腐殖酸粒度测量结果的影响。通过单因素及正交实验确定最优测量条件为:最优分散剂为六偏磷酸钠,超声温度为冰水混合物温度(15℃),超声时间为15 min,分散质质量浓度为0.2 g/L,分散剂质量分数为0.1%。同时,在最优测量条件对防止腐殖酸团聚,提高测量结果准确性作用机理进行了研究。在最优条件下,D_(25)为50 nm,D_(50)为60 nm,D_(90)为70 nm,比表面积达到104.97 m^2/g。经扫描电镜检验,该测试条件下粒度较为准确。

The influences of dispersants, concentration of dispersant, ultrasonic temperature, ultrasonic time and concentration of nanoscale humic acid are studied by laser particle size analyzer. The optimum measurement conditions are determined by single factor and orthogonal experiment, which are shown as follows ： sodium hexametaphosphate as dispersant, 15 ~C of ultrasonic temperature, 15 minutes of ultrasonic time ,0. 2 g/L of the concentration of nanoseale humic acid and 0. 1% of concentration of dispersant. At the same time, the mechanism for preventing agglomeration of nanoscale humic acid and improving the accuracy results under optimum measuring conditions is discussed as well. Under optimal conditions, D25, D50 and Dgo of nanoseale humic acid are 50 nm,60 nm and 70 nm, respectively. The specific surface area can achieve 104. 97 m2 . g-1. These measurement results of laser particle size analyzer are basically identical with the characterization results of SEM.