造纸废水循环中DCS特征参数及其对纸张性能的影响研究

Study on the parameters of DCS and the influence on paper property in papermaking wastewater recycling

为了更好地控制造纸废水循环中的溶解和胶体物质（Dissolved and Colloidal Substance,简称DCS）,通过碎浆和抄片实验模拟造纸生产环节,探究了废水循环次数与DCS各特征参数以及纸张性能参数之间的关系.实验结果表明：DCS微粒的粒径主要分布在100~200nm;随着循环次数的增加,DCS的Zeta电位（绝对值）逐渐减小,且主要由CS贡献;DCS的阳离子需求量主要由DS贡献,DCS和DS的阳离子需求量随着循环次数的增多不断增大;DS是DCS电导率的主要来源,DCS和DS的电导率均随着循环次数的增多逐渐增大;DCS的COD主要由DS贡献,随着循环次数的增多,DCS和DS的COD值逐渐增大;DCS物质以DS为主,DCS和DS的质量分数随水循环次数的增多显著增大,纸张性能参数值随循环次数增多不断降低,当循环次数达到18以上时,DCS物质的累积已对造纸操作和纸张性能产生了严重影响,测得此时DCS物质的COD值为985.23mg·L-1、Zeta电位值为-29.90mV、阳离子需求量为284.30mmol·L-1、电导率为2.85mS.

In order to control the content of DCS（Dissolved and Colloidal Substance）in the papermaking wastewater recycling, we explore the relationship between the number of cycles and the characteristic parameters as well as the performance parameters of paper, and determine the critical value of the characteristic parameters of DCS by simula- ting the paper production with the experiment of pulp and handsheet. The results show that the range of DCS parti- cle size is mainly distributes in the range of 100 to 200 nm. The Zeta potential （absolute value） of DCS decreases with the increasing of the number of cycles, which is mainly contributed by CS. The cationic demand of DCS which is mainly contributed by DS constantly increases with the increasing of the number of cycles. DS is the main source of e- lectrical conductivity in DCS substance. The electrical conductivities of DCS and DS increase with the increasing of the num- ber of cycles. The COD of DCS is mainly contributed by DS, and the COD of DCS and DS increase with the increasing of the number of cycles. The content of DCS is mainly composed of DS, and the contents of DCS and DS significantly increase with the increasing of the number of cycles. The performance parameters of paper continuously reduce with the increasing of the number of cycles. When the number of cycles is more than 18, the accumulation of DCS substance will produce serious negative impact on the paper-making operations and reduce the performance parameters of paper, the COD of DIES, the Zeta potential of DCS, the cationic demand of DCS and the conductivity of DCS substance are 985.23 mg L-1 , -29.90 mV, 284.30 mmol L-1 and 2.85 mS, respectively.