Removal of cadmium [Cd(II)] and copper [Cu(II)] from contaminated water using biochars derived from Clerodendrum viscosum L. Lantana camara L. and sewage

The adsorption of heavy metals, i.e. copper [Cu(II)] and cadmium [Cd(II)], in aqueous solution by biochars was inspected in this study. Clerodendrum viscosum L. Lantana camara L. and sewage were selected for preparation of the biochars at 500°C pyrolytic temperature and referred as CV500, LC500, and SW500, respectively. Batch studies were carried out for dose variation (0.5–16 g L−1), contact time variation (5–120 min), pH variation (2.0–10.0), and concentration variation (10–100 mg L−1). Investigation revealed the maximum removal efficiency for Cd(II) (85.7%) by CV500, while LC500 showed higher removal efficiency for Cu(II) (86.7%) at equilibrium point. SW500 revealed less efficiency in removal of Cd(II) (53.7%) and Cu(II) (60.2%) compared to other studied biochars at equilibrium stage. The maximum theoretical adsorption was 10.5 mg g−1 and 12.3 mg g−1 for Cd(II) and Cu(II), respectively, by CV500 biochar. Langmuir isotherm and pseudo-second order (P-SO) kinetic models were close-fitting models in the present study signifying that the adsorption was a chemical sorption process, with the majority of the adsorption occurring in monolayers. In accordance to Brunauer–Emmett–Teller results, CV500 has a greater surface area (19.1 m2 g−1) than LC500 (15.8 m2 g−1) and SW500 (12.3 m2 g−1), which matches the findings of the field emission scanning electron microscope. The Cd(II) and Cu(II) loading on studied biochars was validated by Fourier transformation infrared analysis and energy dispersive X-ray (EDX) spectroscopy. The oxygen containing functional groups were significantly responsible for sorption of metal ions on investigated biochars. For removing Cd(II) and Cu(II) from wastewater, the current study provides a convenient biochar and sorption technique.