Shell biomass material supported nano-zero valent iron to remove Pb ²⁺ and Cd ²⁺ in water

Abstract

Nanoscale zero-valent iron (NZVI) has a high adsorption capacity for heavy metals, but easily forms aggregates. Herein, preprocessed undulating venus shell (UVS) is used as support material to prevent NZVI from reuniting. The SEM and TEM results show that UVS had a porous layered structure and NZVI particles were evenly distributed on the UVS surface. A large number of adsorption sites on the surface of UVS-NZVI are confirmed by IR and XRD. UVS-NZVI is used for adsorption of Pb 2+ and Cd 2+ at pH = 6.00 in aqueous solution, and the experimental adsorption capacities are 29.91 and 38.99 mg g −1 at optimal pH, respectively. Thermodynamic studies indicate that the adsorption of ions by UVS-NZVI is more in line with the Langmuir model when Pb 2+ or Cd 2+ existed alone. For the mixed solution of Pb 2+ and Cd 2+ , only the adsorption of Pb 2+ by UVS-NZVI conforms to the Langmuir model. In addition, the maximum adsorption capacities of UVS-NZVI for Pb 2+ and Cd 2+ are 93.01 and 46.07 mg g −1 , respectively. Kinetic studies demonstrate that the determination coefficients ( R 2 ) of the pseudo first-order kinetic model for UVS-NZVI adsorption of Cd 2+ and Pb 2+ are higher than those of the pseudo second-order kinetic model and Elovich kinetic model. Highly efficient performance for metal removal makes UVS-NZVI show potential application to heavy metal ion adsorption.

Highly Stable, Mechanically Enhanced, and Easy-to-Collect Sodium Alginate/NZVI-rGO Gel Beads for Efficient Removal of Cr(VI)

“…According to the experimental data of Cr(VI) removal by the SA/xNZVI-rGO beads, the fitting results of the adsorption kinetics are presented in Table 1 . As a result, correlation coefficients (R 2 ) of pseudo-first-order adsorption kinetics are larger than that of pseudo-second-order adsorption kinetics, and the fitted Q e is closer to the measured q e , indicating that the Cr(VI) adsorption by SA/NZVI-rGO gel beads is more consistent with the pseudo-first-order adsorption kinetics, which demonstrates that physical sorption is the main rate control step in adsorption process of SA/NZVI-rGO gel beads [ 57 ].…”

Cobalt/Iron Bimetallic Biochar Composites for Lead(II) Adsorption: Mechanism and Remediation Performance

“…The conical flasks were placed in a constant temperature shaker at 25 • C for 24 h. To compare the effect of pH on Pb 2+ adsorption by BC@Co/Fe-5, 0.05 g BC@Co/Fe-5 was added to 100 mL of a Pb 2+ solution (100 mg L −1 ) with pH values of 2, 3, 4, 5, or 5.5 in a conical flask. The conical flasks were placed in a constant temperature shaker at 25 • C for 24 h. To analyse the kinetics of Pb 2+ adsorption by BC@Co/Fe-5, 0.05 g BC@Co/Fe-5 was added to 100 mL of Pb 2+ solution (100 mg L −1 ) in a conical flask [9]. The conical flask was placed in a constant temperature shaker at 25 • C. At fixed times (1-24 h), 1 mL of the Pb 2+ solution was removed and diluted for analysis [59].…”

“…The thermodynamic data for Pb 2+ adsorption by BC@Co/Fe-5 were fitted using the Langmuir and Freundlich models (Equations and (9), respectively) [62]. q e = q m K L c e 1 + K L c e ( 8) q e = K F c e 1/n (9) where q e is the adsorption capacity at adsorption equilibrium (mg g −1 ), q m is the adsorption capacity at saturation (mg g −1 ), c e is the concentration of Pb 2+ in solution at adsorption equilibrium (mg L −1 ), K L is the Langmuir adsorption constant (L mg −1 ), and K F is the Freundlich adsorption constant (mg 1−n L n g −1 ).…”

“…nZVI has been extensively used in the remediation of hazardous groundwater, permeable reactive barriers, and contaminated subsoil [5,7]. Although nZVI has many benefits for treating heavy metal pollution [8], including high mobility, high reactivity, excellent reducibility, and a large specific surface area, issues such as easy passivation in air and easy agglomeration limit its applicability to environmental remediation [9]. Enhanced stability and higher adsorption capacities have frequently been achieved via composite formation or surface modification.…”

Marine Biomass-Supported Nano Zero-Valent Iron for Cr(VI) Removal: A Response Surface Methodology Study

“…Seashells mainly comprise calcium carbonate, though a small amount of organic matter also exists in them [ 10 ]. After pyrolysis at high temperatures, the organic matter in the seashell will disappear, leaving a porous tubular structure with greatly increased specific surface area [ 11 ]. Furthermore, the seashell surface possesses abundant negatively charged groups and can strongly bind cationic metal ions in solution [ 12 ].…”