Selective removal of arsenic(V) from natural water using N-methyl-d-glucamine functionalized poly(propylene) membranes

• N-Methyl-d-glucamine functionalized membranes were developed by UV-grafting.
• Dense and fibrous membranes were developed for As(V) removal from ground water.
• NMDG was anchored in the poly(glycidyl methacrylate) grafted precursor membranes.
• Flow-though sorption–desorption of As(V) removal was found to be more effective.
• As(V) sorption–desorption from fibrous membrane could be directly coupled to HPLC.

Functionalized membranes for As(V) removal were synthesized by grafting glycidyl methacrylate in the fibrous and microporous host substrates, and subsequently reacting these precursor membranes with N-methyl-d-glucamine (NMDG). These membranes have been characterized and studied for As(V) removal from aqueous solution by the permeation method using dense membranes and flow-through method using fibrous membranes. In the permeation experiment, it was observed that As(V) could be transferred 60% from feed (ground water) to receiver compartment (NaOH) using the dense NMDG-membranes. The lower transfer of As(V) from feed to receiver compartment was due to counter transport of OH− ions from a receiver to a feed compartment. To address this problem, the removal of As(V) by sequential flow-through cycles of the feed and receiver across the fibrous NMDG-membrane was studied. In this mode, 92% of As(V) was sorbed in the fibrous NMDG-membrane in one cycle of 7.5 min for 15 mL feed. As(V) was deloaded to 66% by a single cycle of 0.3 mol L−1 NaOH. The HPLC method was also developed for quantifying As(V) content preconcentrated in a receiver solution. This method could be used for coupling desorption flow through cycle directly to the HPLC system. The reusability experiments showed that the membranes developed in the present work is highly stable and can be regenerated without affecting their As(V) removal efficiency.

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