Arsenic removal using a polymeric/inorganic hybrid sorbent

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Arsenic contamination in groundwater poses significant health risks.
• Effective removal of both As(III) and As(V) species is crucial.
• Existing methods may require pre- or post-treatment and pH adjustments.

Purpose of the Study:

• To investigate the arsenic removal properties of a new polymeric/inorganic hybrid sorbent.
• To evaluate the sorbent's selectivity, durability, and regenerability.
• To compare the performance of the hybrid sorbent with conventional anion exchangers.

Main Methods:

• Development of a hybrid ion exchanger (HIX) by dispersing nanoscale hydrated Fe oxide (HFO) within macroporous cation exchanger beads.
• Conducting fixed-bed column runs to assess arsenic removal efficiency for As(III) and As(V).
• Evaluating sorbent regeneration using caustic soda and assessing its mechanical properties over multiple cycles.

Main Results:

• The HIX sorbent demonstrated highly selective removal of both As(III) and As(V) at circum-neutral pH.
• No additional pre- or post-treatment or pH adjustment was necessary for water treated with HIX.
• The sorbent exhibited excellent mechanical and attrition resistance properties and was efficiently regenerated.
• Intraparticle diffusion was identified as the rate-limiting step for arsenic sorption.

Conclusions:

• The developed hybrid ion exchanger (HIX) is a promising material for selective arsenic removal from contaminated groundwater.
• HIX offers advantages such as high efficiency, durability, and ease of regeneration, eliminating the need for complex water treatment processes.
• The sorbent's performance remained consistent over multiple cycles, indicating its long-term viability for water remediation.