Magnetically separable mesoporous alginate polymer beads assist adequate removal of aqueous methylene blue over broad solution pH

JOURNAL OF CLEANER PRODUCTION

卷:319

Article

Hassan, Masud^1,2  Deb, Amal Kanti^1,2,3  Qi, Fangjie^1,2  Liu, Yanju^1,2  Du, Jianhua^1,2  Fahy, Adam⁴  Ahsan, Md Ariful⁵  Parikh, Sanjai J.⁶  Naidu, Ravi^1,2 

[1] Univ Newcastle, Coll Engn Sci & Environm, Global Ctr Environm Remediat, Callaghan, NSW 2308, Australia

[2] Cooperat Res Ctr Contaminat Assessment & Remediat, Callaghan, NSW 2308, Australia

[3] Univ Dhaka, Inst Leather Engn & Technol, Dhaka 1000, Bangladesh

[4] Univ Newcastle, Ctr Organ Elect, Callaghan, NSW 2308, Australia

[5] Univ Texas El Paso, Dept Chem, 500 West Univ Ave, El Paso, TX 79968 USA

[6] Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA

关键词: Hydrogel beads;    Alginate biopolymer;    Halloysite nanotubes;    Adsorption;    Degradation;    Dyes;   

DOI  :  10.1016/j.jclepro.2021.128694

来源: Elsevier

【 摘 要 】

Adsorption is a promising technology for removal of organic and inorganic contaminants from soil and water system. In this study, magnetically separable mesoporous polymeric beads (NiZnFe4O4-HNT@alg) were synthesised for efficient removal of methylene blue (MB, cationic dye) under broad solution pH (from pH 3.41 to pH 8.43). Alginate biopolymer were used to stabilize halloysite nanotubes (HNTs) and nickel zinc iron oxide nanoparticles (NiZnFe4O4 < 100 nm). NiZnFe4O4 was incorporated onto the polymer beads to generate the adsorbents' magnetic properties and catalytic degradability. The adsorbent (NiZnFe4O4-HNT@alg) have higher surface area (122.43 m2/g), suitable mesoporosity (-6.68 nm), larger pore volume (0.11 cm(3)/g), and abundance of active sites, enabling high adsorption capacity (264 mg/g) of MB. The abundance of hydroxyl, carboxyl, and siloxane groups enabled cationic dye sorption through ionic interaction. The removal efficiency of MB was-99% under a wide solution pH range from 10 mg/L of MB, in which the adsorbent dose was 2 g/L. Both Langmuir (R-2 = 0.99; p < 0.001) and Freundlich (R-2 = 0.99; p < 0.001) isotherm models fitted well, whereas trends of kinetics model fitting are pseudo-second-order (R-2 = 0.99) > intraparticle diffusion (R-2 = 0.93) > pseudo-first-order (R-2 = 0.87). Energy-dispersive X-ray spectroscopy (EDS) elemental mapping demonstrated that MB has a co distribution with silicon, aluminium, and alginate carbon phase but is limited with iron and nickel, indicating HNTs and alginate polymer performed as sorption sites, whereas NiZnFe4O4 performed as a catalyst. The presence (post-sorption) and absence (pre-sorption) of inorganic, total carbon or total organic carbon content at different solution pH, contact time, and initial concentration of MB demonstrated that the adsorbent act as a catalyst as well for degradation of MB. NiZnFe4O4-HNT@alg triggers efficient removal of MB with the assist of adsorption and catalytic degradation at broad solution pH. A comparison in removal of MB by various adsorbents including, biochars, clays, activated carbon, nanoparticles, polymers, nano composites, graphene oxides, carbon nanotubes, and polymer beads with the result of this study were performed, illustrating competitive sorption capacity of NiZnFe4O4-HNT@alg.

【 授权许可】

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