Novel pectin based composite hydrogel derived from grapefruit peel for enhanced Cu(II) removal

• Published in: Journal of hazardous materials 2020-02, Vol.384, p.121445, Article 121445
• Main Authors: Zhang, Wei, Song, Jianyang, He, Qiulai, Wang, Hongyu, Lyu, Wanlin, Feng, Huijuan, Xiong, Wenqi, Guo, Wenbin, Wu, Jing, Chen, Ling
• Format: Article
• Language: English
• Subjects: Adsorption; Alginates - chemistry; Biochar; Charcoal - chemistry; Citrus paradisi; Copper - chemistry; Copper adsorption; Fruit; Grapefruit peel waste; Hydrogel; Hydrogels - chemistry; Pectin; Pectins - chemistry; Pyrolysis; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121445

[Display omitted] •Biochar and low esterified pectin were produced from grapefruit peel waste.•Physically crosslinked biochar/pectin/alginate composite beads were synthesized.•Biochar is help to improve adsorptive, mechanical and thermo-stabilized performance.•BPA beads exhibited good environment adaptability, mechanical and chemical stability.•A better adsorption capacity of Cu(II) than most of reported low-cost adsorbents. Novel biochar/pectin/alginate hydrogel beads (BPA) derived from grapefruit peel were synthesized and used for Cu(II) removal from aqueous solution. FTIR, SEM-EDS, XRD, TGA and XPS, etc. were applied for characterization analysis. The synergistic reinforcing effect of polymer matrix and biochar fillers improved the adsorptive, mechanical and thermostabilized performance of BPA. Factors like component contents of biochar and pectin, pH, contact time, Cu(II) concentration and coexisting inorganic salts or organic ligands were systematically investigated in batch mode. The adsorption isotherms were fitted well by the Freundlich model and the experimental maximum adsorption capacity of optimized BPA-9 beads (mass ratio of pectin to alginate = 10:1) with 0.25% biochar, was ∼80.6 mg/g at pH 6. Kinetic process was well described by the pseudo-second-order model and film diffusion primarily governed the overall adsorption rate, followed by intraparticle diffusion. Thermodynamics analysis suggested spontaneous feasibility and endothermic nature of adsorption behavior. Moreover, BPA also showed better environmental adaptability in the presence of NaCl, MgCl2, CaCl2, EDTA-2Na and CA as well as good adsorption potential for other heavy metal [e.g. Pb(III)]. Crucially, the BPA beads showed good regeneration ability after five cycles. All these results indicated the potential of BPA for removing heavy metal from water.