Simultaneous adsorption of heavy metal ions (Cu2+ and Cd2+) from aqueous solutions by magnetic silica nanoparticles (Fe3O4@SiO2) modified using EDTA

Abstract

In this study, Fe 3 O 4 @SiO 2 magnetic nanoparticles are modified with EDTA and used as a selective and efficient adsorbent for the removal of Cu 2+ and Cd 2+ heavy metals. The Fe 3 O 4 @SiO 2-EDTA nano composite is characterized using scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller. Nanoparticles are separated by an external magnet after the adsorption process. Adsorption equilibrium is achieved in 60 min, and the maximum removal of metal ions is obtained at pH 7. Isotherm analysis indicated that the adsorption data fit well to the Langmuir isotherm model. The maximum adsorption capacities are 79.4 and 73.5 mg/g for Cu 2+ and Cd 2+ , respectively. In addition, adsorption kinetic data agree with pseudo-second-kinetic order for both tested metal ions. Also, the adsorption process efficiency is investigated in the presence of K + , Na + , Mg 2+ , and Ca 2+ cations at the optimal conditions. This study indicates that the Fe 3 O 4 @SiO 2-EDTA is a rapid, efficient, and reusable sorbent to remove Cd 2+ and Cu 2+ cations from contaminated aquatic solution.

Magnetically recoverable steel slag/TiO2 visible‐light‐driven photocatalyst for paraquat degradation

“…The initial concentration of pollutants plays an important role in the photocatalytic process 52,54 . As expected, increasing in the initial concentration of paraquat led to a decrease in the corresponding removal efficiency, where the maximum removal efficiency was 5 mg L −1 (Figure 6).…”

“…Some studies considered the pKa was 11.4, while in the other studies the pKa was around 9 32,51 . Considering the pH ZPC of the SCS@Fe‐TiO 2 and pKa for paraquat, the interaction between SCS@Fe‐TiO 2 and paraquat is high at neutral pH, as the isoelectric charge is zero at this pH range 52 . The highest removal efficiencies were reported at pH values between 6 and 8 27,53 …”

“…32,51 Considering the pH ZPC of the SCS@Fe-TiO 2 and pKa for paraquat, the interaction F I G U R E 4 (a) PL and (b) VSM of SCS@Fe-TiO 2 between SCS@Fe-TiO 2 and paraquat is high at neutral pH, as the isoelectric charge is zero at this pH range. 52 The highest removal efficiencies were reported at pH values between 6 and 8. 27,53…”

Kinetic and Thermodynamic Studies for the Efficient Removal of Methylene Blue Using Hordeum Murinum as a New Biosorbent

“…Various treatment techniques have been used to remove methylene blue dye such as adsorption [12],photocatalysis [13], coagulation/flocculation [14], Fenton [15], and ultrafiltration [16]. Among these treatment processes, adsorption is a very effective treatment methodthat has been widely used for the removal of contaminants from wastewater due to its cost, simplicity, and ease of operation [17][18][19]. Variety of adsorbent materials areused for wastewater treatment.Adsorption using activated carbon is highly effective and the I N ThIs work, hordeum murinum as a sustainable and cost-effective biosorbent material isutilized without any further treatment to remove Methylene blue dye from aqueous solutions.…”

Magnetically Recyclable Wool Keratin Modified Magnetite Powders for Efficient Removal of Cu2+ Ions from Aqueous Solutions

“…The typical nanomaterial sorbents with magnetic features have been widely studied for the removal of heavy metal species because they have high surface area and are easy to separate from aqueous solutions by applying external magnetic fields [18]. Recently, many magnetite (Fe 3 O 4 ) based adsorbents have been developed by incorporation of chitosan [19], chitosan and calcium alginate [20], chitosan and polyether sulfone [21], polyacrylamidoxime [22], asparagine [23], polyethylenimine [24], ethylenediamine coupled with graphene oxide and chitosan-g-poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) copolymer [25], TiO 2 and graphene [26], graphene oxide [27], amino acid and graphene oxide [28], carbon [29], polydopamine or polyamidoamine [30], NH 2 -MIL-125 (Ti) [31], organodisulfide [32], curcumin [33], alginate [34], zeolite and cellulose nanofibers [35], and selective adsorbents ethylene diamine tetraacetic acid [36] and N-(trimethoxysilylpropyl) ethylenediamine triacetic acid [37]. For example, the catechol groups of dopamine can integrate with metal ions and increase the hydrophilic ability of asprepared adsorbents [38].…”