Sustainable mesoporous graphitic activated carbon as biosorbent for efficient adsorption of acidic and basic dyes from wastewater: Equilibrium, kinetics and thermodynamic studies

• Published in: Journal of hazardous materials advances 2023-02, Vol.9, p.100214, Article 100214
• Main Authors: Subba Reddy, Y., Rotte, Naresh Kumar, Hussain, Sahid, Srikanth, Vadali V.S.S., Chandra, M. Ravi
• Format: Article
• Language: English
• Subjects: Acidic and basic dyes; High adsorption capacity; Industrial effluents; Mesoporous graphitic activated carbon; Peltophorum pterocarpum leaf
• ISSN: 2772-4166; 2772-4166
• DOI: 10.1016/j.hazadv.2022.100214

•Mesoporous graphitic AC fabricated from Peltophorum pterocarpum leaf at 550 °C.•MGAC attained high surface area of 881 m2/g and mesopores diameter of 2-6 nm.•Remarkable adsorption capacity exhibited by MGAC towards acidic and basic dyes.•MGAC displayed removal capability for mixture of dyes as well industrial effluents.•MGAC found to have stability and reusability up to 5 cycles of run. Mesoporous graphitic activated carbon (MGAC) was synthesized using inexpensive Peltophorum pterocarpum leaf as a biomass precursor by a simple and efficient method at 550 °C. As prepared MGAC was exhibited mesoporous nature, high surface area as with high adsorption capacity for removal of synthetic dyes as well as industrial effluents. The complete formation of MGAC has been characterized by different analytical techniques such as X-Ray Diffraction (XRD), Raman, Field Emission Scanning Electron Microscopy (FE-SEM), High Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive X-ray Analysis (EDAX), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, Thermogravimetric Analysis (TGA) and the associated Differential Thermal Analysis (DTA). The FE-SEM and HR-TEM images relieved that the presence of an enormous amount of pores and a large specific area for the adsorption of dyes. And also, BET analysis showed 881 m2/g of surface area along with mesopores diameter of 2-6 nm respectively. The XRD and Raman data showed as prepared MGAC in graphitic nature. Further, the MGAC has exhibited good absorption capacity towards acidic dyes such as 868.28 mg/g for Acid blue 113 (AB113) and 151 mg/g for Acid blue 9 (AB9). And also, exhibited towards basic dyes such as 170.10 mg/g for Rhodamine B (RB), 221.81 mg/g for Safranin O (SO) and 272.66 mg/g for Malachite Green (MG)) respectively. Moreover, the optimum MGAC adsorbent dose was found 0.18 g, 0.03 g, 0.06 g, 0.1 g & 0.12 g for AB9, AB113, SO, RB and MG respectively. The equilibrium was attained at 180 min. for all the dyes. Additionally, adsorption of all the dyes followed the Langmuir adsorption isotherm by best fitting of equilibrium as regression coefficient of R2= 0.99, which is confirmed the monolayer coverage of dye molecules on MGAC. Furthermore, the adsorption kinetics data tracked the pseudo second order. In addition, the thermodynamic studies reveled that adsorption is spontaneous as well endothermic and might be chemisorption in nature. Finally, 0.5 g of MGAC dis