A novel highly dispersed calcium silicate hydrate nanosheets for efficient high-concentration Cu2+ adsorption

Currently, the low cost and effective purification toward heavy metal ions in wastewater has garnered global attention. Herein, we used hydrothermal method to prepare highly dispersed calcium silicate hydrate in fluorite tailings. And the stacking thickness of calcium silicate hydrate layered morphology was less than 5 nm. For high concentration Cu2+ purification investigation in wastewater, we found that the equilibrium adsorption capacity reached 797.92 mg/g via the CSH with 3:2 Ca/Si molar ratio, be 1.43~21.8 times than that of reported data. Therein, the metal-metal exchange and deposition are the primary pathways for Cu2+ adsorption, and electrostatic attraction is the secondary pathway. And the relative ~100% removal rate of high-concentration Ni2+ and Cr3+ ions were confirmed via CSH prepared from different tailings. This method offers a cost-effective way to utilize tailings for preparing highly efficient adsorbents toward HMIs removal in wastewater. Heavy metal ions (HMIs) in aquatic systems severely threaten both ecosystem and human health, which has become an important environmental issue. Meanwhile, the increasing tailing accumulation is also facing huge environmental risks. Herein, tailing-derived mesoporous silica was adopted as both silicon source and template to prepare highly dispersed calcium silicate hydrate (CSH). An optimal sample with the ultrathin CSH nanosheets (below 5 nm) exhibited ~100% removal efficiency even the initial concentration of Cu2+, Ni2+ and Cr3+ raised to 400 mg/L, 250 mg/L and 250 mg/L, respectively. This work provides a new insight on utilizing tailing to purify HMIs contaminants.