Aluminium is one of the trace inorganic metals present in drinking water. High aluminium concentrations (3.6 to 6 mg/ℓ) may precipitate as aluminium hydroxide affecting aquatic life. Aluminium is also a suspected agent of neurological disorders such as Alzheimer's disease and senile dementia. The present investigation aims at the sorption of aluminium from drinking water using a low-cost adsorbent. Rice husk char and activated rice husk char were prepared and characterised for various physicochemical properties. The performance of rice husk char (RHC) was compared with other low-cost adsorbents for their aluminium removal capacity. The effect of pH, initial concentration, contact time and temperature was studied for adsorption of aluminium from water under batch conditions. The maximum adsorption capacity was observed with rice husk char at an optimal pH of 4.2. The adsorption of aluminium follows the Freundlich adsorption isotherm. The rate of aluminium adsorption was successfully described by a first-order kinetic model. The thermodynamic study revealed that aluminium adsorption is an exothermic process and the adsorption decreases with an increase in temperature. Nomenclature bLangmuir constant (ℓ/mg) C e Equilibrium aluminium concentration in solution (mg/ℓ) Ct Aluminium concentration in solution at time t (mg/ℓ) ΔG o Gibb's free energy (kJ/mol) ΔH o Enthalpy change (kJ/mol) K Freundlich constant (mg 1-1/n /g ℓ 1/n ) k 1 First-order rate constant (per hour) k 2 Pseudo second-order rate constant (g/mg·h) n Freundlich constant (dimensionless) Q Langmuir constant (mg/g) q e Amount of solute uptake per unit mass of adsorbent at equilibrium (mg/g) R Gas constant (J/mol·K) ΔS o Entropy change (J/mol·K) T Temperature (K) t Time (h)

Adsorption of methylene blue dye over the adsorbent derived from Sapindus seed hull (S) and Camelina (C) is studied. Batch adsorption study on both adsorbents is compared as a function of various parameters such as time, initial concentration and temperature. Langmuir and Freundlich models were fitted to the equilibrium data of methylene blue dye adsorption. Kinetics was evaluated using pseudo-first-and second-order models. Weber Morris model helped to understand the intraparticle diffusion during adsorption of methylene blue molecules. Thermodynamic analysis on both adsorbents revealed the spontaneity of the process. The relative study illustrated a comparison in adsorption capacities among both the adsorbents. Morphology explicated the surface characteristics of both the sorbents. Fourier transform infrared spectroscopy spectrum revealed a variety of functional groups on adsorbents' surface.