College of Resources and Environmental Engineering, State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430081, Hubei Province, China.
Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Sci Total Environ. 2022 Nov 20;848:157431. doi: 10.1016/j.scitotenv.2022.157431. Epub 2022 Jul 18.
Silicon-rich lye (SRL), a byproduct generated from pre-treatment of coal-based solid waste (CSW), was considered as a preponderant silicon source to prepare hierarchically nanostructured calcium silicate hydrate (C-S-H). Through the novel mild-causticization synthesis strategy, C-S-H was prepared under optimal caustic process conditions at time of 3 h, temperature of 80 °C, Ca/Si of 1.25:1, and active CaO to obtain a conversion rate of Si up to 97.33 % during the high-value utilization of SRL. The synthesized C-S-H possesses abundant mesoporous structure and massive exchangeable active sites, whose formation is advanced through an appropriate elevation regulation of caustic temperature and time. The silicate chain depolymerization occurs to C-S-H prepared in the highly alkaline system at higher caustic temperature, longer caustic period, especially at existence of massive sodium ions, but it presents higher polymerization degree at more aluminum co-existing. The adsorption capacity up to 119.27 mg/g for C-S-H presents a valid removal performance toward phosphorus in the wastewater than massive present reports. The removal mechanism of phosphorus can be identified as the surface chemisorption and formation of calcium phosphate co-precipitation. This study can provide considerable and potential guidance to the coordinated disposal between industrial solid wastes and wastewater purification.
富硅堿（SRL）是一种由煤基固体废物预处理产生的副产物，被认为是一种优越的硅源，可用于制备分级纳米结构的硅酸钙水合物（C-S-H）。通过新颖的温和堿化合成策略，在最佳堿化工艺条件下，反应时间为 3 h，温度为 80°C，Ca/Si 比为 1.25:1，活性 CaO 条件下，富硅堿的利用率高达 97.33%，可制备出 C-S-H。合成的 C-S-H 具有丰富的中孔结构和大量的可交换活性位点，其形成是通过适当提高堿化温度和时间来实现的。在较高堿度的堿性体系中，硅酸链解聚会发生在 C-S-H 的制备过程中，这会导致在更高的堿化温度、更长的堿化时间，特别是在存在大量钠离子的情况下，C-S-H 的聚合度会更高。C-S-H 的吸附容量高达 119.27 mg/g，对废水中的磷具有比现有大量报道更高的去除性能。磷的去除机制可以被确定为表面化学吸附和形成磷酸钙共沉淀。这项研究为工业固体废物与废水净化的协同处理提供了有价值的潜在指导。
