Calcium-Modified Fe₃O₄ Nanoparticles Encapsulated in Humic Acid for the Efficient Removal of Heavy Metals from Wastewater

Abstract

Ca-modified Fe3O4 nanoparticles encapsulated in humic acid (HA-Ca/Fe3O4) were produced using a co-precipitation method. Furthermore, the adsorption performance of HA-Ca/Fe3O4 as well as the effect of coexisting ions and mechanisms were evaluated. A good description of the adsorption process was given using pseudo-second-order kinetic and Langmuir models. The adsorption capacities of HA-Ca/Fe3O4 for Pb2+, Cu2+, and Cd2+ were 208.33, 98.33, and 99.01 mg g–1, respectively. The 0.02–0.1 times concentrations in alkali and alkaline-earth metals promoted Pb2+ and Cd2+ adsorption; however, any concentration of alkali and alkaline-earth metals inhibited Cu2+-ion adsorption, probably owing to the differences in ionic radii between the interfering and heavy-metal ions. Pb2+, Cu2+, and Cd2+ removal using HA-Ca/Fe3O4 occurred via ion exchange, complexation of O-containing functional groups, mineral precipitation, and π-electron coordination. A method was proposed to calculate the contribution of these mechanisms to the adsorption process. In practice, HA-Ca/Fe3O4 can remove 99% Pb2+ and 91% Cu2+ and Cd2+ from real wastewater samples. Following five adsorption–desorption cycles, HA-Ca/Fe3O4 adsorption capacity did not change significantly. The aforementioned results indicated that HA-Ca/Fe3O4 presented a good potential in removing heavy metals in wastewater.

Exploiting Hydrogen Interaction of Drugs and Biodegradable Scaffolds Using Nanoparticles Loaded Nanofibers

“…The Fe 3 O 4 nanoparticles and polyvinyl alcohol/chitosan electro‐spun nanofiber was prepared using the electrospinning technique reported in the literature [25–31] . The nanofiber was immersed in 10 mL of dionized water at room temperature.…”

“…The Fe 3 O 4 nanoparticles and polyvinyl alcohol/chitosan electrospun nanofiber was prepared using the electrospinning technique reported in the literature. [25][26][27][28][29][30][31] The nanofiber was immersed in 10 mL of dionized water at room temperature. Cross-Linking between nanofiber, and IBU/TS@Fe 3 O 4 /DST core shell was performed due to the reaction of the hydroxyl group of IBU with amine group of chitosan in the presence of the mixture of EDC and NHS (40 mM EDC and 20 mM NHS) in absolute ethanol under magnetic stirring with 300 rpm at room temperature.…”

Microgels as Smart Polymer Colloids for Sensing and Environmental Remediation

“…They also show mutagenic, teratogenic, and carcinogenic behaviors, which cause major peril to human health, aquatic life, and ecosystems. − Detailed information on some pollutants in the current content is given in Table . Consequently, the elimination of heavy metals and dyes from pollutants is of great significance from the perspective of environmental remediation. , To address these issues, various methods have been developed to treat such water pollutants. − Among various adsorbents reported in the literature, microgel-based adsorbents are significantly important. In the past few years, a good number of microgel-based adsorbents were reported in the literature such as, polyamine-based microgel, N -isopropylacrylamide (NIPAM)-based microgel, and composite microgel for the elimination of dyes and heavy metal ions.…”

Synthesis of Acid Mine Drainage (AMD) Sludge-Derived Al–Fe3O4 as Fenton-like Catalysts for the Efficient Degradation of Tetracycline

“…Fe 3 O 4 is a kind of efficient catalyst with an inverse spinel crystal structure and unique electromagnetic properties, which can be prepared by a simple coprecipitation method . Fe­(II) and Fe­(III) accommodated in the octahedral structure of Fe 3 O 4 allow the Fe species to be reversibly oxidized and reduced, rendering them highly promising candidates for the catalysis elimination of toxic substances. − Fe 3 O 4 is demonstrated to effectively activate peroxymonosulfate (PMS) or hydrogen peroxide (H 2 O 2 ) to generate reactive oxidative species (ROS), such as hydroxyl radicals (·OH), superoxide radicals (O 2 · – ), and singlet oxygen ( 1 O 2 ), leading to the transformation of complex organic pollutants into simple small molecules or even complete mineralization. − However, Fe 3 O 4 is still inevitably limited by the slow mass-transfer process between the solid–liquid interfaces; therefore, its catalytic activity is significantly inhibited.…”