摘要
为明确脱硫石膏改良碱化土壤胶体絮凝过程的离子交换作用,设置了碱化土壤组和碱化土壤胶体组。在不同土水比(1∶5、1∶10、1∶20(m︰V))条件下加入不同量脱硫石膏量(0.1%~2%,m︰m)作为碱化土壤组,以及向利用土水比为1∶100的方法制备碱化土壤胶体中加入不同量的脱硫石膏作为胶体组,以分析脱硫石膏对碱化土壤胶体团聚过程中的临界絮凝值和Na^(+)与Ca^(2+)摩尔比。结果表明,碱化土壤(pH=9.8;EC=496.1μS/cm)胶体的临界絮凝值为MFGDG=0.008 g,胶体与脱硫石膏的质量比为19.4︰1;碱化土壤临界絮凝值为0.5%,胶体与脱硫石膏的质量比为10.4︰1。在临界絮凝值处,碱化土壤所用脱硫石膏量是土壤胶体的1.8倍,碱化土壤组Na^(+)与Ca^(2+)摩尔比为2∶1。随着脱硫石膏施用量的增加,胶体组中絮凝层厚度逐渐变薄,pH降低趋势趋于平缓。土水比越小,混合液中pH越大,加入脱硫石膏后,pH明显下降。土水比为1∶20,碱化土壤组上清液Na^(+)变化逐渐趋于平稳,当加入脱硫石膏后,Ca^(2+)直接吸附在胶体表面发生絮凝现象。研究结果有利于加深脱硫石膏改良碱化土壤中胶体絮凝机理认识,并为确定脱硫石膏改良碱化土壤的适宜施用量提供参考。
In order to clarify the ion exchange effect in the flocculation process of sodic soil reclamation by flue gas desulfurization gypsum, sodic soil groups and sodic soil groups were carried out in the experiments. Under the conditions of different soil-water ratios(1∶5, 1∶10, 1∶20), different amounts of flue gas desulfurization gypsum(0.1% ~ 2%) were added as sodic soil groups, and different amounts of desulfurization gypsum were added to the sodic soil colloid prepared by the method of soil-water ratio of 1∶100 as sodic soil groups. The critical flocculation values and the molar ratio of Na^(+) to Ca^(2+) of flue gas desulfurization gypsum in the process of colloid agglomeration were analyzed. The results showed that the critical flocculation value of the colloid of sodic soil and sodic soil(pH=9.84;EC=496.1 μS/cm) was MFGDG= 0.008 g and 0.5%, respectively. The amount of FGDG used in sodic soil(RS =10.4) was approximately 1.8 times that of the colloid of sodic soil(RC=19.4). At the critical flocculation value, the molar ratio of Na^(+)/Ca^(2+) was 2︰1 in the group of sodic soil. That the amount of FGDG continually added reduced the thickness of the layer of sedimentation and the decreasing trend of pH tended to be flat. The smaller the ratio of soil/water increased pH of the mixture. The content of Na+ in sodic soil group changed little at the ratio of soil/water was 1︰20. Ca^(2+) were directly adsorbed on the colloidal surface and flocculated while applying FGDG. The experimental results deepen the understanding of the colloid flocculation mechanism in the sodic soil improved by FGDG and provide a reference index for the critical dosage of FGDG.
作者
张文新
张文超
王淑娟
李彦
赵永敢
ZHANG Wenxin;ZHANG Wenchao;WANG Shujuan;LI Yan;ZHAO Yonggan(Center for Ecological Restoration of Saline−Alkali,Shanxi Research Institute for Clean Energy,Tsinghua University,Taiyuan 030032,China;Beijing Engineering Research Center for Ecological Restoration and Carbon Fixation of Saline−Alkaline and Desert Land,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China)
出处
《土壤》
CAS
CSCD
北大核心
2021年第3期575-582,共8页
Soils
基金
国家重点研发计划课题项目(2016YFC0501306)
中国博士后科学基金项目(2019M660682)资助。
关键词
碱化土壤
脱硫石膏
胶体絮凝
Sodic soil
Flue gas desulphurization gypsum
Colloidal flocculation
