Β-FeOOH modified polyurethane foam for efficient adsorption of arsenite and arsenate from contaminated water

The prevalent issue of arsenic (As) contamination in groundwater and drinking water has become a significant global concern. While metal oxide-modified polyurethane foam (PUF) provides a cost-effective solution for arsenite [As(III)] and arsenate [As(V)] removal, the absorption mechanism by akaganeite iron oxy hydroxide β-FeOOH-PUF and its practical applications remains understudied. This investigation concentrates on the synthesis of β-FeOOH-PUF through the co -precipitation method utilizing iron chloride (FeCl 3 ) and polyethyleneimine (PEI) as raw materials. In the quest to purify contaminated natural water sources, β-FeOOH-PUF has been employed to adsorb As(III) and As(V). Findings demonstrate successful iron deposition on the foam's surface, generating numerous positively charged Fe O groups. Furthermore, the specific surface area (SSA) of β-FeOOH-PUF exceeded that of the unmodified PUF. Adsorption kinetics and isothermal adsorption analyses revealed a chemical adsorption mechanism for both As(III) and As(V) on a monolayer, with maximum adsorption capacities of 7.37 and 7.96 mg g −1 , respectively. The pH range had minimal impact on adsorption efficiency, with β-FeOOH-PUF demonstrating superior performance over unmodified PUF in removing As(III) and As(V) across various pH levels. The increase in the concentrations of Cl − , SO 4 2− , HCO 3 − , NO 3 − , and PO 4 3− will compete for adsorption sites, change surface charge density, and significantly hinder the adsorption of As(V) by β-FeOOH-PUF. β-FeOOH-PUF can be regenerated under H 2 O, acidic, and alkaline conditions, offering a novel approach to treat inorganic As-contaminated water sources. Therefore, due to its abundant Fe O functional groups, substantial SSA, and recyclability, β-FeOOH-PUF emerges as a highly promising adsorbent for inorganic As(III) and As(V) removal.