Basic and microwave modification processes to produce new activated carbon adsorbents based on Pistacia atlantica Kurdica nuts as carbonaceous raw material; A comparative study on the adsorption and elimination of acid blue 113

Abstract

The nutshell of the pistachio tree was used as a precursor for producing new activated carbon (AC) adsorbent. The raw material was rinsed in H3PO4 (85 % w/w) and heated in a cylindrical furnace at 350 °C/90 min to 700 °C/60 min in a He and NH3 atmosphere. To change the surface chemistry, basic modification of AC was done under the NH3 atmosphere at 700 °C. The FT-IR spectrum showed apparent changes. The microwave, as second modification method, led to significant changes in the porosity properties of AC, especially in the surface area. The SEM images showed the differences in the morphology of the modified and unmodified samples. In the next step, an improved adsorption process was implemented to remove acid blue 113 (AB113). Basic and microwave-modified AC (BMM-AC) showed an enhanced removal efficiency of more than 97.54 % compared to AC, 60.32 %, microwave-modified AC (MM-AC), 73.08 %, and basic modified AC (BM-AC) 88.72 %, which revealed the positive role of the modification methods. Increasing the SBET from 238.8 to 368.6 m2/g using microwaves and changing the surface chemistry by basic modification were significant results of the study. These changes led to the construction of an improved removal process using BMM-AC to eliminate AB113.