Performance and mechanism of zeolite derived from coal gasification coarse slag for adsorbing Ni(II) from wastewater

The heavy metal Ni 2+ in water, posing a serious threat to humans and other organisms through food accumulation, can be removed using high-performance zeolites . The study successfully prepared a highly efficient Y-zeolite adsorbent from coal gasification coarse slag (CGCS) via alkali melt-seed induced hydrothermal synthesis , with an average pore diameter of 8.3 nm. The comprehensive characterization and adsorption experiments were conducted on the synthesized Y-zeolite to investigate diverse factors' influence on performance. The removal efficiency of Ni 2+ reached 98.325 % within 20 min and then stabilized at 99.760 % at a dosage of 1 g L −1 , pH maintained at 7.0, and an initial concentration of Ni 2+ at 100 mg L −1 . The adsorption process conforms to the Pseudo-second-order kinetic model and Langmuir adsorption isotherm model, with the adsorption capacity of 98.943 mg g −1 and the theoretical maximum adsorption capacity of 515.500 mg g −1 . The adsorption mechanism was analyzed by SEM-EDS and FTIR, based on the ion exchange interaction between Ni 2+ and T-O groups. Furthermore, DFT calculations were employed to prove the most stable site for Ni 2+ adsorption on Y-zeolite. The successful adsorption of Ni 2+ on suitable sites located in six-membered rings of SuCage-6mr and Cage-6mr. In conclusion, Y-zeolite showed great potential as an efficient adsorbent for Ni 2+ removal, promoting the comprehensive utilization of solid waste and creating a mutually beneficial outcome. The Y-zeolite adsorbent was successfully synthesized for efficient removal of nickel from wastewater. On the one hand, the resource utilization of solid waste coal gasification coarse slag was achieved, and comprehensive characterization and adsorption experiments were conducted. On the other hand, the adsorption mechanism and optimal sites for adsorption were elucidated by employing a combination of experimental techniques and DFT calculation. • Y-zeolite for Ni 2+ is synthesized from coal gasification coarse slag. • The Method is adapted to effectively use solid waste to address the wastewater. • The optimal removal rate and adsorption time is 99.757 % and 30 min, respectively. • DFT is used to calculate the most stable site for Ni 2+ adsorption on adsorbent.