Agro-waste-based functionalized and economic adsorbents for the effective treatment of toxic contaminants from tannery effluent. (April 2023)

• Record Type: Journal Article
• Authors: Kabir, Mohammad Mahbub; Nahar, Nur; Akter, Mst. Mahmoda; Alam, Faisal; Gilroyed, Brandon H.; Misu, Marjia Mufti; Didar-ul-Alam, Md.; Hakim, Mahmuda; Tijing, Leonard; Shon, Ho Kyong
• Is Part Of: Journal of water process engineering. Volume 52(2023)
• Publication Date: 2023-04
• Subjects: Tannery wastewater -- Cr(VI) adsorption -- Moringa oleifera -- Hydroxyapatite -- Activated carbon -- Surface complexation model; AC Activated carbon -- ANN Artificial neural network -- BET Brunauer-emmett-teller -- BOD Biological oxygen demand -- COD Chemical oxygen demand -- DIW Deionized water -- DLM Double-layer model -- DPC Diphenylcarbazide -- DR Dubinin-radushkevich -- EC Electrical conductivity -- ES Eggshell -- FBR Fixed-bed reactor -- FESEM-EDX Field emission scanning electron microscope-energy dispersive X-ray spectrometer -- FESP Fine eggshell powder -- FTIR Fourier transform infrared -- g/L Gram per litre -- HAP Hydroxyapatite -- ICP-OES Inductively coupled plasma optical emission spectroscopy -- IPD Intra particle diffusion -- MB Methylene blue -- mg/g Milligram per gram -- mg/kg Milligram per kilogram -- mg/L Milligram per litre -- SCM Surface complexation model -- TGA Thermogravimetric analysis; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2023.103578
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: The present investigation explored two novel adsorbents, i.e., hydroxyapatite (HAP) and moringa-modified activated carbon (MMAC) from eggshell and moringa ( Moringa oleifera ) seeds, respectively, for the treatment of tannery effluents (TE). Particular emphasis was given to Cr(VI) adsorption when varying equilibration time, effluent pH, initial concentration of Cr(VI) and temperature. The adsorbents' characteristics suggested significant Cr(VI) accumulation onto the adsorbent's surface, whereas adsorption modelling recommended pseudo-second-order (PSO) and Langmuir models fitted well with the experimental data based on the regression coefficient (R 2 ) values with minimum errors. The surface complexation model (SCM) indicated that speciation of Cr(VI) sorbed complexes formed an inner-sphere compound dominated by acidic pH, validated by pHpzc . The maximum adsorption capacities ( q max ) of Cr(VI) were accounted to be 295 and 280 mg/g for HAP and MMAC, correspondingly. Interestingly, both adsorbents effectively removed other metallic ions; Fe, Pd, Cu and Zn removal was 85 %, while Cd, Ni, and Mn removal was 70 %. The Cr(VI) adsorption processes followed chemisorption mechanisms dominated by the surface complexation phenomenon. The performance of a 100 L packed-bed reactor was evaluated, and the breakthrough time of Cr(VI) adsorption for both adsorbents was 15 min. The adsorbents had splendid regeneration capacities and could be re-used numerous times. In essence, the present study concludes that both adsorbents are highly effective at removing Cr(VI) and other contaminants. The adsorbents are innovative and economical and can be one of the breakthrough feasible options for treating toxic contaminants in a large-scale TE. Graphical abstract: Unlabelled Image Highlights: Two novel adsorbents were developed for the treatment of tannery wastewater. The q max of Cr(VI) was 295 and 280 mg/g for HAP and MMAC, respectively. Fe, Pd, Cu, and Zn removal was 85 %, while Cd, Ni, and Mn removal was 70 %. A 100 L fixed-bed reactor exhibited the highest Cr(VI) removal within 15 min. The adsorbents had splendid regeneration capacities up to the 6 th cycle of re-uses.