摘要
由碱金属的迁移而引起的表面泛碱是使地质聚合物阻截墙结构破坏的主要原因之一。为了抑制地质聚合物的泛碱,掺入纳米Al2O3,含量范围为0.0wt%至2.5wt%,间隔为0.5wt%,将偏高岭土和粉煤灰按4∶1的比例混合作为硅酸盐原料,以氢氧化钠、硅酸钠和水作为复合碱性激发剂,碱性激发剂的掺量为8%(Na2O占原料的质量百分比),硅酸钠模数为1.0,水灰比为0.3,在环境温度为25℃下固化。对所得地质聚合物试块浸出液的碳酸根离子浓度,抗压强度和吸附Cu^2+进行了研究,并结合SEM照片分析了其抑制泛碱的原因。结果表明,通过添加纳米Al2O3,可以抑制地质聚合物表面泛碱并进一步提高抗压强度,随着纳米Al2O3含量的增加,泛碱量先减小后增大,而抗压强度先增大后减小,在添加量为2.0wt%时达到最佳性能。SEM照片表明,纳米Al2O3添加量为2.0wt%时,地质聚合物的微观结构最致密。此外,纳米Al2O3的添加量对最终Cu^2+的吸附量没有影响,在11 d时,不同纳米Al2O3添加量的试块都吸附了溶液中98%以上的Cu^2+。
The surface efflorescence caused by the migration of alkali metals is one of the main reasons for the destruction of the geopolymer barrier wall structure.In order to inhibit the efflorescence of the geopolymer,nano-Al2O3 was incorporated,the content ranged from 0.0wt%to 2.5wt%,and the interval was 0.5wt%,and the metakaolin and fly ash were mixed in a ratio of 4∶1 as the silicate raw material.Using sodium hydroxide,sodium silicate and water as the composite alkaline activator,the sodium silicate dosage was 8%(Na2O as the mass percentage of the raw material),the sodium silicate modulus was 1.0,and the water-raw material ratio was 0.3,and cured in the 25℃ambient temperature.The carbonate ion concentration of the geopolymer test block leaching solution,compressive strength and the ability of adsorb Cu^2+were studied,and the reason for inhibiting efflorescence was analyzed by SEM image.The results show that by adding nano-Al2O3,the efflorescence of geopolymer can be inhibited and further increase the compressive strength.With the increase of the content of nano-Al2O3,the carbonate ion concentration decrease first and then increase,and the compressive strength increase first and then decrease,achieve the best performance at 2.0wt%.SEM image shows that the microstructure of the geopolymer is the densest when the amount of nano-Al2O3 is 2.0wt%.In addition,the amount of nano-Al2O3 has no effect on the amount of Cu^2+adsorbed.At 11 d,the geopolymer with different nano-Al2O3 additions adsorbs more than 98%of Cu^2+in solution.
作者
杨雁惠
洪梅
YANG Yanhui;HONG Mei(College of New Energy and Environment, Jilin University, Changchun 130021, China;National Local Joint EngineeringLaboratory of Petrochemical Pollution Site Control and Remediation Technology, Jilin University, Changchun 130021, China)
出处
《硅酸盐通报》
CAS
北大核心
2020年第3期804-811,共8页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(41530636)。
