Performance Study of a Low-cost Adsorbent-Raw Date Pits-for Removal of Azo Dye in Aqueous Solution.

  The feasibility of using natural waste (raw date pits) as a low-cost adsorbent for the adsorption of an anionic dye (Congo red) from aqueous solution has been investigated. Adsorption optimized conditions were obtained at low dose 1 g/L, initial dye concentration 100 mg/L, pH 2, equilibrium contact time 120 min, and temperature 20 °C. The corresponding adsorption capacity was around 70 mg/g and could reach 150 mg/g by increasing the ionic strength of the dye solution (0.