Characteristics of Nitrate Removal from Aqueous Solution by Modified Steel Slag

Abstract

Steel slag, which makes up a gigantic amount of metallurgical industrial solid waste, was in this experiment successfully synthesized an inexpensive adsorbent used to remove nitrate pollution from aqueous solution. This adsorbent was obtained by mixing steel slag, aluminium hydroxide and deionized water, and aging this at a mass ratio of 3:0.45:2, and then activating it at 800 • C. The physicochemical characteristics of the steel slag before and after modification were investigated to compare the effect of their surface properties on the adsorption behaviour of nitrate. The effects of adsorbent dosage, pH, and contact time on the adsorption process were investigated. The results showed that an increase in specific surface area and the formation of a positive surface of the modified steel slag (MSS) compared with the original steel slag (OSS) could effectively increase the number of the active adsorption sites and nitrate removal ability. The optimum parameters for nitrate removal were as follows: the concentration of nitrate was 20 mg/L, the dosage was 1 g/100 mL, the pH was four, and the reaction time was 180 min. The adsorption capacity of the MSS was approximately 1.9 times that of the OSS. The nitrate adsorption of the MSS was in accordance with the pseudo-second-order model and the Freundlich model, which indicated that the adsorption of nitrate on the MSS was mainly single layer chemical adsorption. The mechanism of nitrate removal mainly included ion exchange, hydrogen bonding, electrostatic interactions and intermolecular interactions. In addition, regeneration experiments indicated that the MSS after regeneration still had the capacity to remove nitrate.

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

“…Thermal activation involves purposeful heat treatment, with and without additives, to increase the amount of crystalline phases in solidified slags. To date, extensive studies have highlighted the benefits of activation of slags for use in the adsorption of cations and anions from industrial effluents and wastewaters [42,57,[59][60][61][62][63][64][65][66]139,140]. In particular, Yang et al [139] investigated the effect of nitrate removal by thermally activated steelmaking slags mixed with Al(OH) 3 .…”

“…The performance of slags modified at 800 • C was 1.9 times higher than that of unmodified slags. The superior performance was attributed to a 3.34-fold increase in specific surface area and a 2-fold increase in the total pore volume of thermally modified slags [139]. Islam and Patel [60] observed an increase in porosity from 9.74% to 17.89%, and in specific surface area from 5.62 m 2 g −1 to 40.89 m 2 g −1 , in BOF slags thermally activated at 1000 • C for 24 h. The fluoride adoption capacity of the thermally activated slags was also significantly higher than that of un-activated slags [60].…”

Complex Fabrication of Zr4+, La3+, and Ce3+ Coordinated Alginate-Assisted Bentonite-Based Hybrid Beads for Nitrate Removal

“…To check enhancement in the adsorption capacity of the synthesized beads, it was compared with adsorbents in the market (Table S5). − It was found that the reported adsorbents exhibit a considerable adsorption capacity, and among them, the metal-ion-loaded AlgBT composite beads had an enhanced adsorption capacity on NO 3 – removal. Moreover, in this study, the adsorbents produced in the form of composite beads, which possess a higher stability compared with the powder form of adsorbents.…”

Experimental and Theoretical Study of the Adsorption Behavior of Nitrate Ions by Layered Double Hydroxide Using Impedance Spectroscopy

“…The Zn 3 Al-Cl-LDH is contacted with a potassium nitrate solution (0.4 g/L) for 5 min, 10 min, 20 min, 30 min, and 60 min. Before washing Zn 3 Al-Cl-LDH after [22]. adsorption and which is intended for the dielectric analysis.…”