The surface morphology and the cross-sections of the prepared papers were imaged using a scanning electron microscope (SEM, JSM-7000F, JEOL, accelerating voltage 2 kV). The loading of ZIF-8 onto CP and TOCNF was evaluated using energy-dispersive X-ray spectroscopy (EDX) with the same instrument. Nitrogen (N2) adsorption-desorption isotherms were measured at 77 K using a Micromeritics ASAP 2020 instrument (U.K.). They were used for the calculation of specific surface areas using the Brunauer-Emmett-Teller (BET) and the Langmuir methods . The t-plot method was used for the calculation of the external surface areas. The pore size distribution was evaluated via the non-local density functional theory (NLDFT) method using N2@77 on a carbon slit. Metal concentration was estimated using atomic absorption spectrophotometer (FAAS) (Buck scientific 210VGC). X-ray photoelectron (XPS) analysis for the CelloZIFPaper_In situ before and after metal adsorption was recorded using Thermo Fischer (Kalpha, Al Kα radiation, 1486.6 eV). FT-IR for the material before and after adsorption was recorded using the KBr pellet method (Nicolet spectrophotometer, model 6700). Thermogravimetric analysis (TGA) was performed under air using Perkin Elmer TGA 7 thermal analyzer apparatus (Shimadzu, Japan) at a heating and airflow rate of 10 o C/min, and 30 mL/min, respectively. The electrochemical measurements were recorded using CorrTest ® (CS350, Wuhan, China). Diffuse reflectance spectroscopy (DRS) measurements before and after metal ions adsorption were recorded using Evolution 220 spectrophotometers coupled with ISA-220 integrating sphere (Thermo Fisher Scientific, U.K.). ). The bandgap energies of ZIF-8, CP, and CelloZIFPaper before and after metal adsorption were calculated using Tauc's plot according to Equation 1 :-