Activated carbon (AC) was produced from date palm leaflets using KOH activation. AC was oxidized with nitric acid and oxidized activated carbon (OAC) was produced. OAC was surface functionalized with tetraethylenepentamine and tetraethylene-pentamine activated carbon (TAC) was obtained. TAC was treated with methyliodide to produce quaternary ammonium salt activated carbon (QAC). Surface area of AC possesses high surface area (1036 m2/g) that tremendously decreased on oxidation (78 m2/g) and surface functionalization (3.8 -6 m2/g). Elemental analysis showed the pres-ence of nitrogen on TAC while nitrogen and iodine were present on QAC. Anion ex-change capacity (AEC) was 24.7 meq/g for QAC and 1.3 meq/g for TAC. Optimum initial pH for arsenate sorption was 5 for TAC and 9 for QAC. The kinetic studies showed that pseudo second order model fit better the sorption kinetic data for arsenate on both carbons than the pseudo first order model. Rising the temperature has led to increased rates of sorption. QAC shows better sorption performance than TAC. The activation energy (Ea) of sorption was found to be less than 40 kJ/mol indicating that the sorption of arsenate on both sorbents is dominantly physical. The equilibrium stud-ies show good fitting with the Langmuir isotherm model than the Freundlich isotherm model with increased sorption as temperature rises. The thermodynamic data showed that the adsorption is spontaneous and endothermic process. The presence of anions has decreased arsenate sorption. QAC shows better recycle properties for arsenate sorption than TAC.