Adsorption of toxic Pb(II) on activated carbon derived from agriculture waste (Mahogany fruit shell): isotherm, kinetic and thermodynamic study

ABSTRACT

An adsorbent, mahogany fruit shell activated carbon(MFSAC), was derived from environmental friendly raw material, i.e. agriculture waste and explored for bench scale adsorption of toxic Pb(II). A facile MFSAC material was synthesised using a chemical activation method using concentrated sulphuric acid as an impregnating (activating) reagent. So derived adsorbent material was characterised by FTIR, XRD, BET, SEM, EDAX, TGA and XPS techniques to know the properties and plausible adsorption mechanism. Bench scale adsorption of toxic Pb(II) and maximum adsorption capacity of MFSAC were exhibited through batch adsorption experiments. The effect of physico-chemical parameters such as pH (1–7), MFSAC amount (0.5–5.0 g L⁻¹), Pb(II) concentration (200–1000 mgL⁻¹), contact period (60–600 min) and orbital shaking speed (60–200 rpm) was studied for maximum removal of Pb(II) upto 99.70 ± 0.17%. The experimental data follow the Langmuir adsorption isotherm with a maximum monolayer adsorption capacity 322.28 mg g⁻¹and pseudo-second-order kinetic uptake rate. The thermodynamic and temperature study revealed that the adsorption process was spontaneous and endothermic in nature (ΔH^o = 43.37 kJ mole⁻¹, ΔS^o = 158.02 J mol⁻¹K⁻¹). Most importantly, the MFSAC adsorbent was successfully regenerated and reused with conspicuous performance up to five consecutive cycles. The bench-scale adsorption with simple synthesis route, good stability and remarkable regeneration capability makes the MFSAC as an encouraging adsorbent for wastewater treatment.

KEYWORDS:

• Activated carbon
• mahogany fruit shell
• Pb(II)
• adsorption
• sulphuric acid

Acknowledgments

Authors are thankful to UGC-SAP and DST-FIST, DST-PURSE for financial support and instrument facilities at the Department of Chemistry, Shivaji University, Kolhapur. Author SAP is thankful for DST-PURSE for Research Assistant Fellowship (NO.SU/EST/PG/1446), and DAE-BRNS for Junior Research Fellowship (36(4)/14/31/2015/36002). Author NSH gratefully acknowledges the Research Associate fellowship (31/11/(1092)/2019-EMR-I), CSIR, New Delhi, India. This work was partly supported by the Human Resources Development Program (No. 20194030202470) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) Grant funded by the Korean Government Ministry of Trade, Industry and Energy and was partially supported by the Priority Research Centers Program through the NRF, Korea funded by the Ministry of Education, Science and Technology (2018R1A6A1A03024334).

Disclosure statement

The authors declare that they have no any known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary material

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