Heavy metal contamination in wastewater has been an issue for the environment and human health nowadays. If these wastewaters are exposed directly to the environment, it will be hazardous for the environment and personal health. So, it is very necessary to treat these ground and surface wastewater before exposing into environment. For this, an effective technique were developed which removed heavy metals from wastewater easily, economically and effectively. The cellulose nano-crystals (CNC) were isolated from banana rachis fibres by a series of chemical treatments as well as 50% H₂SO₄ hydrolysis successively. On the other hand, raw Indonesian type’s bituminous coal was collected from Noapara industrial area, Jashore, Khulna and was pyrolysed at 700°C, activated by 2M HCl at 700°C and also carbonised at 500°C followed by activation with 30% H₃PO₄ acid. In this process, adsorbent of modified charcoal-CNC composites was used for the removal of methyl orange dye and five heavy metals, such as Ni(II), Pb(II), Cr(III), Cd(II) and Co(II)), from wastewater and the uptake capacity, selectivity and removal efficiency were also discussed. The filtering efficiency of wastewater purifications were characterised by FTIR, X-RD, TGA, SEM analysis. Finally, wastewater solution and the filtrates solutions were characterised by UV-Vis, and AAS techniques.