Development and Application of a Composite Water-Retaining Agent for Ecological Restoration in Arid Mining Areas

Ecological restoration in arid coal-mining regions faces extreme challenges due to soil infertility, salinization, and water scarcity. This study addresses these limitations in the Santanghu Shitoumei No. 1 open-pit mine (Xinjiang), where gypsum gray-brown desert soil, minimal rainfall (199 mm/yr), high evaporation (1716 mm/yr), and persistent gale-force winds exacerbate revegetation efforts. To overcome the high cost, short lifespan, and poor practicality of commercial water-retaining agents, we developed a novel humic acid (HA) and sodium carboxymethyl cellulose (CMC) composite water-absorbing resin (HA-CMC). Optimal synthesis parameters-identified as acrylic acid (AA)-carboxymethyl cellulose (CMC)-humic acid (HA)-Acrylamide (AM)-N,N'-methylene diacrylamide (MBA)-Ammonium persulphate (APS) = 100%:15%:4.5%:25%:0.6%:0.8%-yielded effective crosslinking, confirmed via FTIR and SEM. Performance benchmarking against existing agents demonstrated superior attributes. Field application in the mine's demonstration area significantly enhanced surface vegetation and soil fertility, confirming the resin's potential for large-scale soil remediation and ecological restoration in arid mining environments.