Development of Novel Hybrid Inorganic-Organic Polymer Membrane Systems for Simultaneous Desalination and Emerging Contaminant Removal from Brackish Water Sources in North-East Nigeria

Access to safe drinking water in North East Nigeria is severely compromised by both salinity and emerging organic contaminants including pesticides and pharmaceutical residues in brackish groundwater sources, creating demand for advanced membrane systems that can simultaneously address both challenges. This research develops novel hybrid inorganic-organic polymer membrane systems for simultaneous desalination and emerging contaminant removal, investigating the fundamental structure-performance relationships governing dual-function separation in water sources representative of Borno, Yobe, and Adamawa states. Hybrid membranes were synthesised by incorporating metal-organic framework nanoparticles of zeolitic imidazolate framework-8 and HKUST-1 types, functionalised graphene oxide, and zeolite nanoparticles into polyamide thin-film composite and polysulfone hollow fibre substrates. Synthesis conditions including nanoparticle loading, cross-linking density, and interfacial polymerisation chemistry were systematically varied. Membrane characterisation included water contact angle, surface zeta potential, hydraulic permeability, rejection of sodium chloride, magnesium sulphate, and representative emerging contaminants including carbamazepine, diclofenac, and atrazine. Antifouling performance against natural organic matter was assessed by irreversible fouling resistance measurement. A mechanistic transport model incorporating solution-diffusion and pore-flow contributions was developed to interpret rejection behaviour across varying solute physicochemical properties. Results demonstrate that zeolitic imidazolate framework-8 incorporation at 0.15 percent weight fraction in polyamide composite membranes improved sodium chloride rejection from 97.2 to 98.9 percent while simultaneously increasing carbamazepine rejection from 81 to 96 percent. Water permeability increased by 34 percent relative to unmodified polyamide composite, attributed to facilitated water transport through metal-organic framework pores. The transport model correctly predicted the observed permeability-selectivity trade-off deviation from the Robeson upper bound for all hybrid membrane compositions. The research provides a validated framework for designing next-generation dual-function membranes for water security in arid and semi-arid regions of North East Nigeria. Keywords: hybrid membrane, desalination, emerging contaminants, metal-organic framework, North East Nigeria