Separation Of Metal Ions Research Articles

Utilization of desalination wastewater for SOx, NOx, and CO2 reduction using NH3: Novel process designs and economic assessment

Many countries discharge considerable amounts of desalination wastewater directly into the ocean, which cause environmental pollution, destruction of ecosystems, and economic losses. Desalination wastewater contains valuable metal ions such as Na+, Ca2+, and Mg2+, which react with carbonate and sulfate ions; therefore, it has the high potential to reduce the NOx, SOx, and CO2. Thus, this study designed process for the utilization of desalination wastewater to capture and utilize NOx, SOx, and CO2 using NH3. A process model was developed, which was composed of following three steps: (1) metal ion separation in desalination wastewater based on pH swing processes for separating Ca2+ and Mg2+ as Ca(OH)2 and Mg(OH)2, respectively; (2) NOx capture and SOx capture and utilization using generated Mg(OH)2, and (3) CO2 capture and utilization using NH3. Subsequently, to demonstrate the economic validity of the suggested process, an economic assessment was conducted and total annualized costs (TACs) of the conventional and proposed processes were compared. As a result, ~96 % of NOx was captured, the SOx capture efficiency was 99 %, and ~94.7 % of CO2 was captured. Thus, a reduction of 11.2 % in the TAC was achieved using the proposed process, indicating its high economic feasibility.

Magnetically derived fabrication of aligned porous poly(sulfonated polystyrene-co.-chitosan) monolith as a high efficient adsorbent for metal ions separation

Designing and tuning towards the porous structure of adsorbents is of great importance for promoting the adsorptive performance. Herein, a magnetic-induced copolymerization method is applied to generate an aligned porous structure in the aligned porous poly(SPS-co.-CTS) monolith. Typically, the aligned macropores primarily derives from the equilibrium of the magnetic dipolar force to the thermodynamic Brown force by tuning the applied magnetostatic field intensity to 25 mT. Due to the aligned macroporous structure, the monolith features with low back pressure, low mass transfer resistance and high adsorptive capacity. The hydrophilicity of the monolith surface is further improved by capping chitosan activated by amino onto its porous surface via the Hinsber reaction. Detail analyses are performed by a series of physical characterizations, by which exhibit the aligned macropores centering at 5.18 μm, specific surface reaching 54 m2 g−1 and large porosity. Finally, batch adsorption experiments confirm that the adorptive behaviors to Cu2+ ions and Co2+ ions submit to the Langmuir model and Pseudo-second order adsorption kinetics. Most intriguing, the film mass transfer ([kLa]f) has been stabilized due to the aligned macropores, thus facilitating the porous diffusion ([kLa]d) and improving the chromatographic performance of the monolith. All results demonstrate that the aligned porous poly(SPS-co.-CTS) monolith promises broad applications in the field of wastewater remediation.

Study of the Applicability of a Functionalized Silica-Based Adsorbent for Pd(II) Separation from Simulated High-Level Liquid Waste

In this study, to separate Pd(II) and other metal ions from high-level liquid waste (HLLW) for the effective use of limited resources, the applicability of a functionalized silica-based adsorbent was evaluated via batch-adsorption and chromatographic separation experiments using simulated HLLW containing 15 metal ions. The functionalized silica-based adsorbents used were 3-mercaptopropyl-functionalized silica gel (MP-Si), 2,4,6-trimercaptotriazine-functionalized silica gel (DMT-Si) triaminetetraacetate, sodium salt-functionalized silica gel (TAAcONa-Si), and 3-aminopropyl-functionalized silica gel (AP-Si) with different structures. Among them, MP-Si, DMT-Si, and TAAcONa-Si showed an adsorption capacity for Pd(II). In addition, the adsorption of Pd(II) onto TAAcONa-Si had relatively high adsorption stability for HNO3 concentration and contact time. Moreover, regarding the maximum adsorption amount of Pd(II), adsorption onto MP-Si and DMT-Si with thiol had a larger amount than that of TAAcONa-Si with polydentate ligand. The adsorption of Pd(II) onto TAAcONa-Si was preferable under low-temperature conditions, indicated by thermodynamic analysis. The chromatographic results showed the complete separation of Pd(II) from simulated HLLW using TAAcONa-Si by 0.1-M thiourea–0.01-M HNO3 solution. On the basis of these results, it is possible to change metal ion selectivity using a functionalized silica-based adsorbent having a different structure, and the separation of Pd(II) and other useful metal ions from HLLW is applicable.

Designing and integrating NOx, SO2 and CO2 capture and utilization process using desalination wastewater

• A novel capture and utilization process for NO x , SO x , and CO 2 is proposed. • The process utilizes metal ion in desalination wastewater. • Using the Ca(OH) 2 for desulfurization, the additional CO 2 emission is prevented. • NO x can be utilized as Ca(NO 3 ) 2 using Ca(OH) 2 as a reactant. • Using the desalination wastewater, all of the absorbent complete can be substituted. Numerous industries are facing serious environmental contamination, because of the significant emission of nitrogen oxide (NO x ), sulfur dioxides (SO 2 ), and carbon dioxide (CO 2 ) and it has become imperative to reduce these gaseous emissions. To reduce pollution caused by gaseous emissions, desalination wastewater is possible to be used because it contains highly concentrated useful mineral ions such as Ca 2+ , Mg 2+ , and Na + which react with carbonate, nitrogen, and sulfate ions. This work designed and integrated NO x , SO 2 , and CO 2 capture and utilization processes using desalination wastewater for cleaner production. To design and integrate the NO x , SO 2 , and CO 2 capture and utilization process, a process model is developed based on validated experimental data. The proposed process model comprises the following three steps: (1) electrolysis and metal ion separation of desalination wastewater to produce NaOH, Mg(OH) 2 , and Ca(OH) 2 ; (2) NO x and SO 2 capture and utilization via Ca(OH) 2 ; (3) CO 2 capture and utilization using NaOH, Mg(OH) 2 and Ca(OH) 2 . Then the economic feasibility of the suggested process is demonstrated compared to conventional process by economic assessment. As a result, the NO x and SO 2 are captured and utilized at about 90% and 99% respectively. In addition, the CO 2 is captured at about 91% and the conversion yields of each carbonate are 99% and 63% respectively. To demonstrate the economic feasibility of the proposed process, two cases are set. Case 1 is the case that employs selective catalytic reduction (SCR), wet flue gas desulfurization (WFGD), and a CO 2 capture process that uses amine as a CO 2 absorbent with an electrodialysis reclaiming unit. Case 2 is the case that employs SCR, WFGD, and the CO 2 capture process that uses amines with an ion-exchange resin reclaiming unit. As a result, the total annualized cost of the proposed process was ∼7.9% and 14% lower than those of Case 1 and Case 2, respectively.

Enhancement of antifouling properties, metal ions and protein separation of poly(ether-ether-sulfone) ultrafiltration membranes by incorporation of poly ethylene glycol and n-ZnO

Composite polymeric membranes with enhanced anti-fouling properties, antimicrobial activities and flux were produced via the phase inversion technique using poly (ether-ether-sulfone) (PEES)/polyethylene glycol (PEG) and n-ZnO. SEM and ATR-FTIR spectroscopy were used to study the morphological and chemical properties of the resulting ultrafiltration membranes. PEG and n-ZnO concentration has an effect on membrane morphologies, ultrafiltration performance, thermal characteristics, metal ion separation studies, surface hydrophilicity and anti-fouling capabilities. The permeate flux increased when the PEG concentration was raised. This results revealed that adding PEG and n-ZnO to membranes increased their surface hydrophilicity and anti-fouling properties. The inclusion of 1.5 wt % n-ZnO and 5 wt % PEG to the pristine PEES membrane resulted in a higher flux of 233.76 L m-2 h−1, 70.09 % of water content, 47.46° of contact angle, the porosity of 30.20 %, and hydraulic resistance of 0.22 kPa/Lm−2h−1. Anti-fouling properties of the fabricated membrane were assessed using a model foulant BSA, which revealed a high flux recovery ratio value. As a result, the PEG and n-ZnO incorporated membrane is more hydrophilic than the virgin membrane. In addition, the prepared PEES/PEG/n-ZnO membrane showed a significant increase in metal ions and protein rejection. Furthermore, an antibacterial test of the membrane revealed that the PEG and n-ZnO composite membrane outperformed the bare PEES membrane in terms of antibacterial capabilities. Overall, the findings reveal that combining n-ZnO and PEG resulted in a membrane with improved anti-fouling capabilities and hydrophilicity, making it suitable for water purification.

Designing Metal-Chelator-like Traps by Encoding Amino Acids in Zirconium-Based Metal–Organic Frameworks

Metal chelators and porous sorbents are two of the forefront technologies applied for the recovery and separation of hazardous and/or valuable metal ions from aqueous solutions (i.e., polluted water sources, metal-rich mining wastewaters, acid leachates, and so forth). The transfer of the metal coordination functions of metal chelators to chemically stable host materials had only limited success so far. Here, we report the installation of natural acids (i.e., malic acid, mercaptosuccinic acid, succinic acid, fumaric acid, and citric acid) and amino acids (i.e., histidine, cysteine, and asparagine) within a porous zirconium-based trimesate metal–organic framework (MOF), namely, MOF-808. Applying this strategy, we were able to produce a pore environment spatially decorated with multiple functional groups usually found in commercial chelator molecules. The chemical stability of the amino acid molecules installed by the solvent-assisted ligand exchange has been studied to delimitate the applicability window of these materials. The adsorption affinity of MOF-808@(amino)acids in static and column-bed configurations can be fine-tuned as a function of the amino acid residues installed in the framework. MOF-808(amino)acid columns can be applied efficiently both for water remediation of heavy metals and for the separation of metal ions with different acidities. For instance, the initial trends for the dispersion of rare-earth elements have been identified. Electron paramagnetic resonance and inelastic neutron scattering spectroscopy reveal that MOF-808@(amino)acids stabilize metal centers as isolated and clustered species in a coordination fashion that involves both the amine and thiol functionals and that affects the vibrational freedom of some of the chemical groups of the amino acid molecules. The metal-ion stabilization within amino acid-decorated MOFs opens the avenue for application for pseudo biocatalysis purposes in the near future.

Synthesis of stimuli-responsive pillararene-based supramolecular polymer materials for the detection and separation of metal ions

A stimuli-responsive supramolecular polymer network (G-(CN)2⊂BXDSP5) with aggregation-induced emission (AIE) properties has been efficiently constructed by host–guest interactions between pillar[5]arene derivative BXDSP5 and a homoditopic guest G-(CN)2, which shows not only excellent fluorescence properties due to the AIE effect but also desirable ion-sensing abilities in both solution and solid states, holding great potential in the applicable fluorescence detection for Fe3+. The resultant G-(CN)2⊂BXDSP5 can be transformed into supramolecular polymer gel at high concentration via multiple noncovalent interactions, showing multi-stimuli-responsiveness in response to temperature change, mechanical force, and competitive agent. Meanwhile, the xerogel of supramolecular polymer material has been successfully used to remove Fe3+ from water with high adsorption efficiency. In addition, an ion-responsive film based on supramolecular polymer has also been developed, which can serve as a practical and convenient fluorescence test kit for detecting Fe3+.

Recent Advances in Graphene Oxide‐Based Membranes for Heavy Metal Ions Separation

AbstractGraphene oxide (GO)‐based membranes have been widely investigated for separation of dyes, salt ions, heavy metal ions, and biomolecules due to their high mechanical strength, single‐layered structure, large surface area, and high affinity. However, due to irregular pore structure, nanochannels, interlayer distance, easy functionalization, swelling effect, and chemical stability under aqueous environment limited their separation efficiency. In this review, different fabrication methods of GO membranes are summarized. The role of functionalization and cross‐linking on membrane's structural properties, separation performance, and practical applications are discussed. Further, the GO‐based membranes (GOMs) for separation and removal of heavy metal ions are discussed in detail. The factors which influence the separation performance are also highlighted. Finally, recommendations and future directions are suggested.

Understanding the coordination behavior of quaternary ammonium and phosphonium nitrate ionic liquids under gamma irradiation: A combined spectroscopic investigation

In the process of spent nuclear fuel reprocessing, it is very essential to investigate the radiation stability of the extracting phase.From the ionic liquid (IL) family, quaternary ammonium or phosphonium based ILs: methyltrioctylammonium nitrate ([N1888][NO3]) or trihexyl(tetradecyl)phosphonium nitrate ([P66614][NO3]) have many commendable features while being used as the solvent for the extraction and separation of the target metal ions from nuclear waste solution. In this context, a comparative investigation on the irradiation effect on the stability of [N1888][NO3] and [P66614][NO3] and their coordination ability towards acid and metal ion was furnished systematically. A marginal change in the extraction ability was acquired upon irradiation. The spectroscopictechniques such as UV–Visible, ATR-FTIR and fluorescence spectroscopy were employed to deduce the intrinsic role of the applied dose. The peak at ∼ 260 nm in UV–Visible spectra is broadened and red shifted upon irradiation for both ILs with substantial shift in [P66614][NO3]. FTIR spectra suggests the appearance of new peaks at 752 cm−1 upon radiation exposure for both ILs indicating the formation of degraded products of NO3– ion (bending vibration of NO2. radical) and - CH2 group (cleavage of - H. radical). A remarkable difference in the peak intensity and shape for [P66614][NO3] as compared to [N1888][NO3] confirms the radiation tolerance level of two ILs. For both irradiated and unirradiated ILs, the presence of water coordination was confirmed due to the peak at (bending mode of H2O), which later showed blue shift upon metal (or acid) loading.Luminescence patterns of Eu(III) in the irradiated ILs realizes an adequate quenching of Eu(III) emission in [P66614][NO3] in comparison to [N1888][NO3] which was less affected by the radiation. In all the spectroscopic evidences specify the vital role of NO3– anion in altering the radiation stability of ILs.

A novel ion exchange resin as an alternative for conventional chelates for separation and removal of toxic metal ions from industrial wastewater

Tamarind Kernel-Power (TKP), a naturally occurring polysaccharide, has been used for the synthesis of a novel ion exchange resin, namely Tamarind triazine methyl sulphamic acid (TTMSA). The resin acts as a scavenger for toxic metal ions from the effluents of various industries. Characterization of resin has been done by FTIR, TGA and elemental analysis. Various physico- chemical properties of resin were analyzed including ion-exchange capacity, % nitrogen content, bulk density, bulk volume and moisture content. The resin was found to be stable with good reproducibility, good ion exchange capacity and selectivity for toxic metal ions. The partition coefficient values and percentage adsorption of various metal ions on the newly synthesized resins were determined by batch method with the help of Atomic Absorption spectrophotometer. The efficiency of resin was studied for up to 10 cycles. Analysis has shown that the adsorption of different metal ions on TTMSA resin followed the order Fe+2 >Cu+2> Zn+2>Pb+2>Cd+2. A suitable and cost-effective method was employed to reach the result of this experiment.

A comparison of the extraction behaviour of tris(2-methylbutyl) phosphate and tri-n-alkyl phosphates for the separation of metal ions for U–Zr and U–Pu–Zr systems by cross-current mode

Abstract Even though, pyroprocessing is considered as a suitable technique for metal fuel processing, attempts are being made in our laboratory to develop a solvent extraction based process as an interim method. Since, the metallic fuels contain considerable amount of Pu(IV) and Zr(IV), the use of conventional extractant tri-n-butyl phosphate (TBP) for reprocessing may pose problems due to third phase formation. In the exploration for the identification of an alternate extractant in the organophosphate family, tris(2-methylbutyl) phosphate (T2MBP), a branched isomer of tri-n-amyl phosphate (TAP) was found to be a potential extractant for nuclear fuel reprocessing. In this context, batch wise extraction and stripping studies with a feed solution containing U(VI) and 6 wt% Zr(IV) were carried out with unirradiated and irradiated 1.1 M solution of T2MBP in n-dodecane (n-DD) and the results were compared with corresponding solutions of TBP and TAP in n-DD. Among all these systems under identical conditions, third phase formation was observed only in the case of irradiated TBP system which makes U–Zr fuel reprocessing difficult using TBP as the extractant. Furthermore, studies have also been carried out with U–Pu–Zr feed solution to understand the extraction and stripping behaviour of these extractants. The stage wise and cumulative percentage of extraction and stripping for each metal ion of these systems were evaluated. Overall, these batch studies indicated that, T2MBP system has comparable extraction and stripping behaviour with U–Zr and U–Pu–Zr feed solutions and T2MBP exhibits better separation factor than TBP.

Cu(II) ions removal from wastewater using starch nanoparticles (SNPs): An eco‐sustainable approach

AbstractThe complex structured starch particles were reduced to the nanoscale size range through hydrolysis utilizing low concentration acid assisted by ultrasound irradiation. The synthesized starch nanoparticles (SNPs) were characterized by transmission electron microscopy (TEM), Fourier‐transform infrared (FTIR), and X‐ray diffraction (XRD) techniques. The synthesized SNPs possessed surface activated entities, as many cationic functional groups were confirmed through the FTIR spectrum. Also, these SNPs were effectively utilized to separate heavy Cu metal ions from the synthetic ion solution. The SNPs were characterized using field emission scanning electron microscope (FESEM), X‐ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis for the surface modification after the adsorption process. The weak electrostatic interaction between the SNP surface and Cu ion was confirmed by the XPS spectrum and energy‐dispersive X‐ray spectroscopy. The maximum efficiency of Cu ions removal was about 93% at an optimal pH 5 and 25 mg/ml dosage. The adsorption equilibrium was obtained in 60 min. The nitrogen isotherm BET analysis of SNPs after adsorption shows a higher specific surface area of 18.552 m2/g, attributed to the interaction and presence of Cu ions on the SNP surface. The process feasibility was validated by the Langmuir isotherm model. The process exhibits pseudo‐second‐order adsorption kinetics and follows the Langmuir isotherm. The RL predicted by the Langmuir isotherm mechanism is 0.017, implying favourable adsorption. The process is reproducible and allows for the separation of heavy metal ions from the wastewater through biosorption effectively.

Scrutiny of physico‐chemical properties of extractant‐diluent phase: Keystone of extraction systems

AbstractSolvent extraction is one of the hydro metallurgical techniques adopted due to its ease for efficient separation of metal ions. The separation and extraction of metals are enabled using privileged metal distribution between the aqueous and organic phase. Commercially available solvent extractants and recently the designer solvents like ionic liquids have gained adequate attention in the area of separation science for the retrieval of different metal ions. Diluents play an important role by ensuring the improved hydrodynamics of the extraction system. The physico‐chemical characteristics of the organic phase solution need to be scrutinized thoroughly in order to optimize the extraction conditions. Investigation on the interaction between extractant and diluent at molecular level is vital for the assessment of extraction efficiency. Density, viscosity, dielectric constant, refractive index, conductivity, and acoustic properties provide evidence on the molecular organizations between these unlike molecules. The aim of this review is to project on the importance of physical, chemical, and thermodynamic properties for fabricating an efficient combination of extractants‐diluents to achieve maximum extraction output.

A Comprehensive Review on Analytical Applications of Hydrazone Derivatives

This review covers a summary of analytical applications of hydrazone derivatives in a systematic manner (1961-2021), which will help researchers in the design and development of hydrazone derivatives as potential candidates in medicinal, pharmaceutical, catalytic, and analytical chemistry, especially in the separation, identification, and detection of several metal ions, anions, organic molecules, and water in various real and synthetic samples. In addition to these, hydrazone derivatives may be used as light emitting diodes, for synthesis of DSSC, nanoparticles and polymers, as corrosion inhibitors, as dyes, etc. This review does not include all papers in this field, but it does synthesize all significant works on the subject.

ZIF-67 modified MXene/sepiolite composite membrane for oil–water separation and heavy metal removal

In this study, polyvinylpyrrolidone (PVP) was used as a cross-linking agent leading to ZIF-67 in-situ grow on the surface of sepiolite (Sep) to increase the specific surface area and space volume of Sep. Subsequently, a hydrothermal synthesis method was used to form a stable super-hydrophilic composite membrane from the composite MXene by polydopamine. Compared to the MXene/PDA/Sep (MPS) composite membrane, the composite membrane with ZIF-67 exhibited improved hydrophilicity and heavy metal separation. In addition, the introduction of negatively charged Sep@ZIF-67–24 (SZ-24) increased the number of adsorption active sites and negative potential for the surface of the membrane, and this was conducive to the demulsification and adsorption of oil–water emulsions. The MXene/PDA/Sep@ZIF-67–1 (MSZ-1) composite membrane had excellent separation effects on surfactant-stabilized emulsions (SSEs) and surfactant-free emulsions (SFEs) oil–water emulsions which were above 99.4 %. Furthermore, the separation effect on oil–water, under extreme water conditions, was greater than 99 %. The MSZ-1 composite membrane can achieve excellent separation of heavy metal ions, especially Cu2+ that the rejection was 79.9 %, under high flux and extreme conditions. Therefore, the MSZ-1 composite membrane has broad application prospects in oil–water treatment and heavy metal separation.

Novel pulp mill wastewater recovery process for CO2 and SOx utilization

Pulping industry has a pulp mill process that emits a significant amount of carbon dioxide (CO2) and sulfur oxides (SOx). The pulp mill wastewater has a high potential for reducing pollution caused by CO2 and SOx because it contains useful mineral ions in high concentrations, such as Ca2+, Mg2+, Na+, and K+ that react with carbonate and sulfate ions. In this study, we develop a novel pulp mill wastewater recovery process for CO2 and SOx utilization. To design the CO2 and SOx capture and utilization process using pulp mill wastewater, a process model is developed based on validated experimental data. The developed process model comprises the following three steps: (1) metal ion separation of pulp mill wastewater to produce KClO4, Mg(OH)2, and Ca(OH)2; (2) SOx capture and utilization using Ca(OH)2 and SOx, utilized as desulfurization gypsum; (3) CO2 capture via generated KClO4, and the captured CO2 is utilized as carbonate using Mg(OH)2 and Ca(OH)2. Accordingly, the economic feasibility of the suggested process model is demonstrated by calculating the pay-back period in economic assessment. As a result, the desulfurization efficiency was 99% with high-purity gypsum production. In addition, ∼98.2% CO2 was captured. Furthermore, the annual profit was increased by USD 94,469, and thus, the pay-back period was determined as 8.4 y.

Application of Poly(Ethyl Eugenyl Oxyacetate) Compounds as the Ions Carrier for Heavy Metals Separation and Separation of Fe and Ni in Ferronickel Using Liquid Membrane Transport Method

Poly(ethyl eugenyl oxyacetate) (PEEOA) had been synthesized for separating heavy metals like Fe(III), Cr(III), Cu(II), Ni(II), Co(II), and Pb(II) by liquid membrane transport method. The effects of pH, ion carrier volume, stripping concentration, transport time, and metal ion concentration were investigated to obtain optimum conditions. Experimental results showed that optimum pH occurred at pH 4 for Fe(III) ions and pH 5 for others. Carrier volumes were optimum at 8.5 mL for Fe(III) and Pb(II) ions but 7.5 mL for others. The optimum concentrations of the stripping phase were 2 M for Fe(III) and Cu(II) ions, 1 M for Cr(III), Ni(II), Co(II) ions, and 0.5 M for Pb(II) ion. Transport times were optimum at 36 h for Fe(III) and Co(II) ions and 48 h for others. The optimum metal ion concentrations were 0.25 mM for Fe(III) and Cr(III) ions, while other ions were 0.1 mM. The response of PEEOA to Fe(III) ion was the best with selectivity order, Fe(III) > Cr(III) > Pb(II) > Cu(II) > Ni(II) > Co(II). PEEOA also could separate Fe and Ni in a ferronickel sample whose transport percents were 8.87 and 0.92%, respectively. Hence, PEEOA is reasonably effective as an ions carrier for separating metal ions individually or ionic mixture and also in a ferronickel compound.

Enhanced mercuric ions reduction over mesoporous S-scheme LaFeO3/ZnO p-n heterojunction photocatalysts

BackgroundThe separation of heavy metal ions from industrial wastewater is a great challenge regarding environmental remediation. MethodsFollowing this, a Sol-gel technique was successfully utilized to synthesize novel mesoporous LaFeO3/ZnO nanocomposites containing varying concentrations of LaFeO3 nanoparticles. Mercury ions (Hg2+) were photo-reduced over the prepared mesoporous LaFeO3/ZnO heterojunctions in the presence of HCOOH which plays the role of the hole scavenger. Significant findingIllumination by visible light showed that mesoporous LaFeO3/ZnO nanocomposite containing 3.0 wt.% LaFeO3 maintained a noticeable ability of mercury ions photo-reduction. The complete photo-reduction of mercury ions was achieved and was estimated as 16.6 times greater when compared with pure ZnO after 30 min of exposure. Major factors that contributed to the remarkable mercury ions photoreduction ability of LaFeO3/ZnO nanocomposite heterojunction system are summarized as the enhanced visible light absorption, effective separation of generated charges, distinct large surface area, and distinguished mesoporous texture. The outcomes presented here represent an example of an outstanding approach for adequate removal of mercury ions that could be adopted efficiently in various industrial fields.

Design of novel seawater bittern recovery process for CO2 and SOx utilization

Considerable seawater bittern is produced during salt production. Seawater bittern can be used to reduce CO2 and SOx because of the presence of valuable mineral ions, such as K+ and Mg2+, which react with the carbonate and sulfate ions present in high concentrations. In this study, a novel seawater bittern recovery process is proposed for CO2 and SOx utilization. The proposed process has the following steps: (1) metal ion separation of the seawater bittern to produce KOH and Mg(OH)2; (2) SOx capture and utilization using the generated Mg(OH)2; (3) CO2 capture and utilization using the generated KOH. The pay-back period (PBP) was calculated to verify the economic feasibility of the proposed process. The results revealed an SOx and a CO2 capture efficiency of approximately 99 % and 98 %, respectively. Furthermore, the annual net revenue was approximately 153,439 USD/y based on the profit obtained from the generated product and savings on absorbent. Thus, the PBP was approximately 6.2 y.

Molecular dynamics and network analysis reveal the contrasting roles of polar solutes within organic phase amphiphile aggregation

Amphiphile self-assembly in non-polar media is often enhanced by polar co-solutes. This is observed within many biphasic separations processes, where amphiphiles mediate transport of water and acid into organic solution. A myriad of competitive intermolecular interactions have thus far prevented a fundamental understanding of the individual and dual roles of these polar solutes upon amphiphile self-assembly in non-polar media. Toward this end, the current work employs classical molecular dynamics and intermolecular network analyses to deconstruct the individual affects of water and nitric acid upon the self-assembly of N,N,N’,N’-tetraoctyl-3-oxapentanediamide (TODGA), a prevalent amphiphile extractant used in metal ion separations. In the absence of acid, and at low water concentration, H2O is found to promote local dimer and trimer formation of TODGA, however as [H2O]org increases, preferential self-solvation leads to large (H2O)n clusters that cause TODGA clusters to sorb to the (H2O)n periphery and supports extended aggregation. Addition of HNO3 to the humid solutions disrupts the water hydrogen bond network and inhibits the formation of large water clusters - thus preventing extended aggregation behavior and encouraging local aggregation. Prior experimental observations of enhanced TODGA self-assembly under these conditions are attributed primarily to the role of water rather than co-extracted HNO3, thus providing valuable new insight into the means by which extractant aggregation can be tuned within separations processes. The different roles of polar co-solutes, that derive from their individual hydrogen bonding capabilities and competitive interactions in the context of preferred solvation environments, is of fundamental importance amphiphile behavior in non-polar media.