Adsorbent dosage Adsorption 2 Activated carbon 1 Adsorption process 1 Agricultural wastes 1 Aluminum 1 Batch adsorption experiments 1 Cation exchanges 1 Central composite rotatable design 1 High potential 1 Inductively coupled plasma 1 Inductively-coupled 1 Interactive effect 1 Ions 1 Layered double hydroxides 1 Metal concentrations 1 Ni(II) removal 1 Nickel 1 Optimization 1 Optimization parameter 1 Optimum conditions 1 Pilot studies 1 Response surface methodology 1 Soil mechanics 1 Surface properties 1 adsorption 1 spent mushroom farming waste (SMFW) 1