| Summary: | The current study is focused on the facile synthesis of zeolitic imidazolate framework-8 (ZIF-8) at room temperature
14 using three different solvents: ammonia solution (ZIF-8 (N)), aqueous solution (ZIF-8 (H)), and methanol (ZIF-8 (M)).
15 The ZIF-8s produced have high crystallinity with different sizes and shapes. The morphology of ZIF-8 (H) resembled
16 the mixture of cubic and the rhombic dodecahedron with truncated corners, whereas ZIF-8(M) occurred as the most
17 stable rhombic dodecahedron, and ZIF-8(N) appeared as cubes with truncated corners. ZIF-8 (N) had the largest
18 average particle size of 573 nm, followed by ZIF-8 (H) and ZIF-8 (M) with average sizes of 108 nm and 62 nm,
19 respectively. ZIF-8 (N) showed a rapid Pb(II) and Cd(II) adsorption, within 15 min, while ZIF-8(H) achieved Pb(II)
20 and Cd(II) equilibrium within 240 min, and 300 min for ZIF-8 (M). The adsorption of Pb(II) and Cd(II) is best fitted
21 with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacities for Pb(II)
22 and Cd(II) sorption were 454.55 and 312.50 mg/g for ZIF-8 (H), 434.78 and 277.78 mg/g for ZIF-8 (M), respectively,
23 and 476.19 and 263.16 mg/g for ZIF-8 (N), respectively. All of the prepared ZIF-8s showed a promising competency
24 as adsorbents for the removal of Pb(II) and Cd(II) from an aqueous solution.
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