In situ preparation of magnetic Fe₃O₄.Cu₂O.Fe₃O₄/cryogel nanocomposite powder via a reduction–coprecipitation method as adsorbent for methylene blue water pollutant

Abstract

Magnetic nanocomposites have attracted great attention as adsorbents for the removal of water pollutants, which respond to an external magnet that is used to remove both pollutants and composite nanomaterial traces from water. They are environmentally friendly and effective adsorbents for water treatment. In this respect, a simple in situ preparation method was used to prepare cryogel powder composite based on Fe 3 O 4 .Cu 2 O.Fe 3 O 4 nanomaterials. The ionic cryogel based on 2-acrylamido-2-methylpropane sulfonate sodium salt and styrene sulfonate sodium salt was prepared by crosslinking polymerization at low temperature. The new magnetic nanoparticles based on Fe 3 O 4 .Cu 2 O.Fe 3 O 4 were successfully prepared inside the cryogel networks by a simple reduction-coprecipitation method based on reaction of Fe 3+ with sodium sulfite and Cu 2+ in the presence of hydroxylamine and ammonia solution. The thermal stability, accurate Fe 3 O 4 .Cu 2 O.Fe 3 O 4 content, magnetic properties, crystal lattice structure, particle sizes and morphology of the prepared cryogel composite were evaluated. The optimum conditions such as pH, contact time, adsorbate concentrations, adsorption equilibrium and adsorption kinetics were investigated to determine the efficiency of the prepared composite as an adsorbent to remove toxic methylene blue (MB) pollutant from aqueous solution. The data for MB adsorption confirmed the high ability of the prepared composite to remove more than 4.696 mmol L −1 of MB from water during 6 min. The regeneration and reuse experiments showed excellent data for the synthesized new dye as an effective adsorbent for water treatment.

Preparation of magnetite and silver poly(2‐acrylamido‐2‐methyl propane sulfonic acid‐co‐acrylamide) nanocomposites for adsorption and catalytic degradation of methylene blue water pollutant

“…It was previously reported that the in situ technique is preferred for the formation of metal and metal oxide NPs inside the polymer templet to form polymer nanocomposites . The dispersion of metal or metal oxide into the polymer templet increased with increasing chelation of metal cations with the polymer reactive groups . In this respect, the present work aimed to form Fe 3 O 4 and Ag NPs inside the AMPS/AAm hydrogel or microgel by reduction of the absorbed metal cations using ammonia (NH 3 ) and NaBH 4 , respectively, as represented in the Experiment section and Scheme .…”

“…The AMPS/AAm gel was selected as a templet to prepare magnetic and silver nanocomposites based on the reactivity ratios of AMPS to AAm which confirm the formation of alternate to random copolymers with high contents of AAm to AMPS . It was previously reported that the in situ technique is preferred for the formation of metal and metal oxide NPs inside the polymer templet to form polymer nanocomposites . The dispersion of metal or metal oxide into the polymer templet increased with increasing chelation of metal cations with the polymer reactive groups .…”

“…Moreover, nano‐hybrid magnetic materials have been subsequently used to adsorb water pollutants by magnetic separation or photocatalytic degradation of pollutants . The magnetic iron oxide polymer composites or nano‐hybrids can promote the magnetic separation of nano‐adsorbents after the adsorption of pollutants from water . Iron oxide nanoparticles (NPs) have low removal efficiency when used as adsorbents for water pollutants due to their agglomeration.…”

“…It was previously reported that diquat herbicide is not adsorbed by Fe 3 O 4 NPs . Hence additional magnetite surface treatments are required to increase the sorption of pollutants on adsorbents by embedding the iron oxide into polymer matrices using the in situ technique to control their magnetic properties so they can be easily magnetically separated after the water treatment …”

“…The application of nanocomposite polymer hydrogels in the field of water treatment requires mechanically strong gels with long‐term reusability and controlled biodegradability . In our previous work, it was found that the in situ technique is more effective for the preparation of polymer nanocomposite adsorbents than the mixing technique . In the present work, 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and acrylamide (AAm) were selected as ionic and nonionic monomers, respectively, to prepare hydrogels and microgels.…”