Biosorption of nickel by ground fallen waste coffee plant leaves powder: Equilibrium, kinetics, Thermodynamics and Optimization (RSM)M. Tukaram Bai, P. Venkateswrlu, Husam Talib Hamzah, V. Sridevi and Ch.A.I. RajuE3S Web Conf., 552 (2024) 01050DOI: https://doi.org/10.1051/e3sconf/202455201050