Mild Hydrothermal Synthesis of 11Å-TA from Alumina Extracted Coal Fly Ash and Its Application in Water Adsorption of Heavy Metal Ions (Cu(II) and Pb(II))

Abstract

Non-biodegradable copper (Cu) and lead (Pb) contaminants in water are highly toxic and have series adverse effects. Therefore, it is very important to extract heavy metals from wastewater before it is discharged into the environment. Adsorption is a cost-effective alternative method for wastewater treatment. Choosing a low-cost adsorbent can help reduce the cost of adsorption. In this study, conversion of reside after extracting aluminum (REA) produced by sub-molten salt method transform high-alumina coal fly ash (CFA) into 11Å-tobermorite to adsorb Cu(II) and Pb(II) from aqueous solutions at room temperature. The synthesis of the adsorbent was confirmed using scanning electron microscope (SEM), X-ray diffractometer (XRD) and Brunauer–Emmett–Teller (BET) method surface analysis. To study the adsorption characteristics, factors such as initial Cu(II) and Pb(II) concentration, pH, contact time, adsorption characteristics and temperature were investigated in batch mode. The maximum adsorption capacity of Cu(II) and Pb(II) was 177.1 mg·g−1 and 176.2 mg·g−1, respectively. The Langmuir adsorption model was employed to better describe the isothermal adsorption behavior and confirm the monolayer adsorption phenomenon. The pseudo-second-order kinetic model was used to highlight Cu(II) and Pb(II) adsorption kinetics. Thermodynamic analysis indicated the removal Cu(II) and Pb(II) by TA-adsorbent was a nonspontaneous and exothermic reaction. The obtained results are of great significance to the conversion of industrial waste to low-cost adsorbent for Cu(II) and Pb(II) removal from water.

Preparation of biomass-based hydrogels and their efficient heavy metal removal from aqueous solution

“…This indicates that STS-PAA requires a small amount of energy to convert the reactants into products when adsorbing Pb 2+ , Cd 2+ and Hg 2+ . ΔG is a positive value, which is very common in the adsorption system ( Unuabonah et al, 2008 ; Lu et al, 2016 ; Choi et al, 2017 ; You et al, 2018 ; Yang et al, 2022 ). Using the linear graph of the thermodynamic model to estimate the thermodynamic parameters may introduce some errors, which may transfer the values from one extreme boundary to another.…”

Calcium Silicate Hydrate Cation-Exchanger from Paper Recycling Ash and Waste Container Glass

“…The batch removals of aqueous Pb 2+ , Cd 2+ , and Cs + from single metal ion solutions by TOB-7 are compared with those of other bespoke and waste-derived tobermorites in Table 6 [18,20,22,[24][25][26][27]35,41,42,53,72,[75][76][77][78][79]. The ranges of batch uptakes of Pb 2+ reported for bespoke (0.08-1.85 mmol g −1 ) [53,74] and waste-derived tobermorites (0.06-2.25 mmol g −1 ) [18,20,22,24,26,41,42,79] are comparable and do not appear to be related to either crystallinity or Al-content (Table 6).…”

“…The batch removals of aqueous Pb 2+ , Cd 2+ , and Cs + from single metal ion solutions by TOB-7 are compared with those of other bespoke and waste-derived tobermorites in Table 6 [18,20,22,[24][25][26][27]35,41,42,53,72,[75][76][77][78][79]. The ranges of batch uptakes of Pb 2+ reported for bespoke (0.08-1.85 mmol g −1 ) [53,74] and waste-derived tobermorites (0.06-2.25 mmol g −1 ) [18,20,22,24,26,41,42,79] are comparable and do not appear to be related to either crystallinity or Al-content (Table 6). The removal of Cd 2+ is generally less extensive than that of Pb 2+ by both bespoke (0.04-1.36 mmol g −1 ) [53,75] and waste-derived tobermorites (0.111-1.52 mmol g −1 ) [18,20,22,24,25,42,79], and is similarly unaffected by structural order and composition.…”

“…PRA and WCG-derived tobermorite (this study) 1.78 ± 0.04 0.65 ± 0.06 0.36 ± 0.03 Bespoke tobermorites [75] 1.85 0.945 -Bespoke tobermorites [76] --0.84 Bespoke tobermorites (microwave synthesis) [77] --0.6 Bespoke tobermorites [53] 0.08-0.895 0.04-1.36 -Bespoke tobermorites [72] --0.564-0.572 Container glass-derived tobermorite [18] 1.66 ± 0.05 0.48 ± 0.01 -Sodium silicate and PRA-derived tobermorites [25] -0.63-1.12 -Snail shell ash and waste glass-derived tobermorite [22] 0.060 0.111 -Blast furnace slag-derived tobermorites [27] --0.112-0.587 Asbestos-bearing disaster waste-derived tobermorite [35] --0.31-0.51 Fly ash-derived mesoporous tobermorite [26] 1.287 --Alumina-extracted coal fly ash-derived tobermorite [42] 1.636 0.937 -Alumina-extracted coal fly ash-derived tobermorite [41] 0.850 Cement bypass dust and glass-derived tobermorite [20] 2.25 1.52 -Incineration fly ash-derived tobermorite [78] --0.40 Bottom ash-derived tobermorite/zeolite mixture [79] 0.381 0.196 Coal ash-derived tobermorite/zeolite mixture [24] 1.98 1.31 -Pb 2+ and Cd 2+ ions are rapidly exchanged for labile inter-layer cations within a few hours, and subsequently also replace structural Ca 2+ ions within the tobermorite lattice over a longer timeframe. In this respect, the steady state uptake of divalent cations is usually established between 3 and 10 days [18,20,22,24,26,41,42,53,75,79]. In addition to tobermorite, other common components present in waste-derived hydrothermal products such as calcite and portlandite, undoubtedly contribute to the removal of Pb 2+ and Cd 2+ via the precipitation of solubility-limiting phases [75], and the amorphous calcium (alumino)silicate gel phase may also enhance the overall sorption capacity.…”

Preparation of zirconium oxide nanoparticles from rosette concentrate using two distinct and sequential techniques: hydrothermal and fusion digestion

“…Hydrothermal technology has also expanded into much broader fields that include many disciplines. As a new method, hydrothermal digestion technology has been developed in recent years to selectively extract one metal from the other (Naymanbaev 2009;Yang 2022;Al-Ghouti et al 2021). This technology has an extraordinary reaction rate since it operates at a higher controllable temperature and pressure than conventional hydrometallurgical procedures.…”