Abstract: The goal of creating montmorillonite-based artificial algal crusts is to stabilize the topsoil layer,prevent surface erosion,fix the matrix lead,and avoid the threat of tailing lead leaching to ecological security. These artificial cyanobacterial biocrusts are being built in semi-arid lead mining areas because of the extreme environmental problems,such as water shortage,surface degradation,and lead pollution. In this work,lead-based sandy soil was covered with artificial algal crusts made of Microcoleus steenstruppi and montmorillonite (MT). The optimal input of montmorillonite to encourage the growth of cyanobacteria was achieved by studying the morphological changes of artificial cyanobacterial biocrusts and tracking the changes of biological markers of algal crusts. The capacity of artificial cyanobacterial biocrusts on matrix lead to fix lead and its detoxification process were investigated by the use of particle size,Zeta potential,SEM-EDS,lead chemical form,FTIR,and XRD analysis. The findings revealed that M500 had the highest development of cyanobacteria,with a substantially greater filament density than M 0. On day 62,M500,the best treatment group,had a chlorophyll a level that was 1. 9 times higher than M0. Cyanobacterial filaments,extracellular polymers,and montmorillonite can all include matrix lead. On day 62,M500,the best treatment group,had a chlorophyll a level that was 1. 9 times higher than M0. Cyanobacterial filaments,extracellular polymers and montmorillonite can all include matrix lead. On day 62,the ideal treatment group M500 had a total solid lead level of 231. 97 μg / cm2,which is 1. 2 times that of M 0. Montmorillonite encourages the transformation of unstable weak acid exchangeable and carbonate-bound lead compounds into more stable organic-bound and residual lead compounds during the lead fixation process. The transformation of matrix lead into extremely low solubility basic lead carbonate and basic lead phosphate is promoted by artificial cyanobacterial biocrusts,according to characterisation. Thus,the artificial cyanobacterial biocrusts based on montmorillonite increase their fixing effect on the matrix lead and achieve the body′s detoxifying impact by lowering the bioavailability of lead. This work discloses the lead fixation mechanism of artificial cyanobacterial biocrusts and offers for the first time a novel way for treating lead polluted soil utilizing clay type artificial cyanobacterial biocrusts. Additionally,it has significant theoretical and practical implications for the practice of green water and green mountain engineering. It offers a sustainable and scientific management technique for ecological restoration in semi-arid lead poisoned mining sites.

Key words: montmorillonite,microcoleus steenstruppi,artificial cyanobacterial biocrusts,lead pollution,mine restoration