Adsorptive removal of phenol from aqueous solution using chemically modified Saccharum officinarum biomass: modelling and process optimisation

ABSTRACT

This article proposes a way to extract phenol from aqueous solution as synthetic wastewater through the biomass (saccharum officinarum)-derived ZnCl₂-activated carbon named as SBAC. The surface area and pore radius of SBAC were found to be 415.960 m²/g and 0.725 nm, respectively. Batch adsorption studies were carried out to analyse the percentage removal of phenol under various conditions, such as initial concentration (50–500 mg/L), initial pH (2–12), adsorbent dosage (2–40 g/L), temperature (283–303 K) and contact time (30–360 min). The proposed study has achieved ~94% of maximum phenol extraction, with the adsorption capacity of 9.44 mg/g at an initial concentration of 50 mg/L, dose of 5 g/L, pH of 5.5, contact time of 60 min and temperature of 303 K. The kinetic and equilibrium studies confirmed pseudo-second-order reaction and Radke-Prausnitz isotherm as the best fit. In thermodynamic study, the negative values of ΔG⁰_ads (−21.448 to −24.330 kJ/mol), ΔH⁰ (−1.059 kJ/mol) and positive value of ΔS⁰ (0.072 kJ/mol K) confirmed the spontaneity, exothermic nature and randomness of adsorption process, respectively. Regeneration and reusability of SBAC showed 86.45% removal of phenol till fifth consecutive cycles. Cost analysis revealed that the developed SBAC was 14 times less expensive (~718 INR/ 9 $) than commercial activated carbon. From the present study, the developed adsorbent found to be good for wastewater treatment under ambient reaction conditions to achieve clean water.

KEYWORDS:

• Aqueous solution
• biomass
• adsorption
• phenol
• isotherms
• kinetics
• thermodynamics

Acknowledgments

The authors would like to acknowledge the “Department of Civil Engineering” and “Department of Chemistry”, Visvesvaraya National Institute of Technology, Nagpur, India, for providing instrumentation facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Associated content

Figure S1–S6 represent various isotherm plots using Langmuir, Freundlich, Temkin, Redlich-Peterson, Toth and Radke and Prausnitz models for SBAC at five different temperatures, viz. 283 K, 293 K, 303 K, 313 K and 323 K, respectively. Figure S7 represents thermodynamics Van’t Hoff plot from Radke–Prausnitz isotherm constants and Figure S8 represents the mass balance diagram for a single-stage batch sorption. Table S1 represents cost of 1 kg SBAC preparation and Table S2 represents the cost comparison of SBAC with commercial activated carbon.

Author contributions

Dilip H. Lataye: Guidance, conceptualization and research review. Darla R. Upendra: Experimentation, interpretation and original draft. Zakiullah Zaidi: writing-review and editing, and validation.

Supplementary material

Supplemental data for this article can be accessed here.