Evaluation Low Cost Adsorbent of Walnut Bark Granule for Methylene Blue Dye Removal from Aqueous Environments

Background & Aims of the Study: Methylene blue (MB) is a risk for human and environment. Adsorption process is one of the removal mechanisms of MB. The purpose of this research was the evaluation of low cost adsorbent of walnut bark granule for MB dye removal from aqueous environments. Materials & Methods: In this experimental research, the effect of various operating parameters such as dose of dye (100-500 mg/L), contact time (10-50 min), adsorbent dosage (1-5 g/L) and pH (3-8) was investigated. Color concentration was measured by spectrophotometer (Shimadzu Model UV-120-02) at 663 nm wavelength and pH was analyzed through pH meter (Digimed model DM-20, Digicron AnaliticaLtda, Sao Paulo, Brazil). Results: The findings of this research were showed that the walnut bark granule was able to remove up to 41% of MB dye (100 mg/L) from solutions at initial pH 7. Removal efficiency was increased by adsorbent dosage and contact time. MB concentration has a reverse effect on removal. Also, the equilibrium data were also fitted to the Freundlich equilibrium isotherm model (R2=0.95). Conclusions: Present study showed that use of walnut bark granule, as an absorbent, could be utilized in methylene blue removal. Therefore, considering the production wastes of this compound, utilization the essence of this substance as inexpensive absorbent with inexpensive and available raw material is clear.