Specific Adsorption Research Articles

Molecularly imprinted polymer based on magnetic porous cellulose for specific adsorption of tetracyclines: Preparation, characterization, property evaluation, and application

A magnetic porous cellulose molecularly imprinted polymer (MPCMIP) based on tetracyclines was prepared with Fe3O4 as the magnetic core and porous cellulose as the carrier. The appearance, characteristic chemical bonds, crystal structure, thermal stability, and magnetism of MPCMIP were systematically characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. The adsorption performance of MPCMIP to tetracycline, demeclocycline, and minocycline were comprehensively investigated by static adsorption, dynamic adsorption, and adsorption experiments under different temperature and pH conditions. MPCMIP performed good adsorption performance and fast adsorption rate for tetracyclines, and adsorption quantity and efficiency of MPCMIP were four times and twice that of traditional molecularly imprinted polymer (MIP), respectively. It can be seen that the introduction of magnetic porous cellulose effectively improved the adsorption performance of the MIP. Moreover, MPCMIP showed good adsorption stability under different temperature. The adsorption properties of MPCMIP under neutral and alkaline conditions were better than those under acidic conditions. Selective experiment was conducted with the amoxicillin and levofloxacin as the coexisting interfering compounds for the three tetracyclines. The results showed that MPCMIP possessed good imprinting effect with the impact factor values for tetracycline, demeclocycline, and minocycline of 1.49, 1.66, and 3.14, respectively. Compared with interfering compounds, MPCMIP showed excellent selectivity to tetracyclines with the selectivity factor up to 36.9. Moreover, MPCMIP exhibited better selectivity towards tetracyclines than traditional MIP according to the higher imprinting and selectivity factors of MPCMIP. The simulation of hydrogen bonding interaction and electrostatic potential analysis determined that MPCMIP mainly adsorbed TCs through the hydrogen bonding and electrostatic interactions. The results of adsorption/desorption cycling experiments indicated that MPCMIP had good reusability with 95.5% of adsorption performance after four cycles. Finally, MPCMIP combined with high-performance liquid chromatography were triumphantly used to adsorb and detect the tetracycline, demeclocycline, and minocycline in river, beef, and milk samples. Furthermore, the MPCMIP method exhibited higher sensitivity, accuracy, and selectivity than the traditional method.

Aptamer functionalized magnetic hydrophobic polymer with synergetic effect for enhanced adsorption of alternariol from wheat

A new adsorbent based on aptamer functionalized magnetic hydrophobic polymer (MHbPA) was developed for specific and efficient adsorption of alternariol (AOH). Through the synergistic effect of aptamer-AOH affinity and hydrophobic interaction of polymer, enhanced adsorption properties had been realized, in which AOH aptamer was the first selected through capture-SELEX with good specificity and affinity, and the targeting polymer was designed based on the hydrophobicity of AOH to increase the interaction. The proposed MHbPA demonstrated a high adsorption capacity of 187.6 ng/mg for AOH. The adsorption behavior was considered as Langmuir adsorption model and pseudo-secondary kinetic adsorption model. Notably, the adsorption of AOH in wheat powder samples could be accomplished within 10 mins with acceptable recoveries. The as designed adsorbent with synergistic effect provides new insights into the development of enhanced pretreatment materials for mycotoxin monitoring in complex food matrices with specific aptamer and targeting polymer.

Highly efficient and targeted adsorption of Congo Red in a novel cationic copper-organic framework with three-dimensional cages

Metal-organic frameworks (MOFs) with a three-dimensional (3D) caged structure and charged networks are promising adsorbents for separation and purification applications. However, it is a challenge to synthesize the MOFs in crystalline structures with a targeted ability of efficiently removing and reutilizing the individual diazo dye from sewage. Here, we report the synthesis of a novel copper-organic framework (Cu-MOF) with a 3D caged stucture and cationic networks using CuCl2 and a triazole ligand (methyl-1H-1,2,4-triazole-3-carboxylate MTC). The novel Cu-MOF exhibited highly efficient and targeted adsorption, separation and recovery characteristics for Congo Red (CR). Specifically, the maximal adsorption capacity was 119.76 mg·g−1, and the adsorbed CR can be efficiently released in NaCl-DMF solution with a recovery rate of almost 100%. After suffered from three adsorption–desorption cycles, the Cu-MOF could still reach a adsorption rate of >85% and maintain an intact skeleton structure. The batch-equilibrium experiment combined with density functional theory calculation further revealed that the adsorption process was spontaneous and exothermic, following the pseudo-second-order kinetic equation with monolayer diffusion. The specific adsorption of Cu-MOF for CR was precisely generated through electronic interaction with the –NH2 and -SO3 groups, exhibiting the adsorption energies of −2.16 eV and −2.04 eV, respectively. The two-dimensional correlation spectroscopy analysis comfirmed that the energy distribution in CR adsorption was dominated by electrostatic interactions, followed by π-π stacking and van der Waals interactions. In summary, our work not only presents a promising strategy for the targeted separation and purification of CR from wastewater, but also contributes to the design of highly efficient MOF-adsorbents for other organic pollutants.

Facile activation of natural calcium-rich sepiolite with oxalic acid for selective Pb(II) removal: Highly-efficient performance, mechanisms and site energy distribution

The design and development of adsorbents with high efficiency, selectivity, and economy for Pb(II) are essential to environmental governance and ecological safety. Herein, an oxalic acid (OA) activated natural sepiolite (nSEP) composite for highly efficient Pb(II) removal was prepared by a facile impregnation strategy. The OA activated nSEP nanocomposite (OA-nSEP) was characterized by various instrumental techniques and its adsorption performance towards Pb(II) was further evaluated through a series of static and dynamic experiments under various environmental conditions. Results revealed that OA reacted with the calcium impurities in nSEP to form calcium oxalate, causing mesoporous structure and larger specific surface area of OA-nSEP. The obtained OA-nSEP possessed super high Pb(II) adsorption capacities (858.4–1252 mg/g), which were much higher than that of most modified clays or conventional materials. The average adsorption site energy and the standard deviation of the site energy distribution were analyzed to investigate the strength of Pb(II) binding onto OA-nSEP and the adsorption site heterogeneity. Mechanism studies confirmed that oxalate groups exerted a primary role in the adsorption process. X-ray diffraction and X-ray photoelectron spectrometry (XPS) unveiled that the coordination of oxalate with Pb(II) and precipitation of lead oxalate was responsible for the high efficiency and selectivity. Distinguishing feature of high adsorption capacity, specific selective adsorption, abundant availability, and splendid reusability make the OA-nSEP a promising candidate for eliminating Pb(II) in practical scenarios.

Doping of porous carbons with sulfur and nitrogen markedly enhances their surface activity for formaldehyde removal

The surfaces of phosphoric acid activated carbon, referred to as CG, and steam activated one, referred to as SX, were modified through an introduction of S- and N- groups originated from thiourea. The prepared samples were used for formaldehyde removal at room temperature. Heating at 450, 600 and 950 °C altered both surface chemistry and porosity. The extents of these modifications depended on the type of carbon. Using thiourea as the modifier resulted in an incorporation of significant amounts of nitrogen and sulfur to the carbon matrices. Their speciation depended on the heat treatment conditions. The activity of samples heated at 450 °C was governed by amine groups of thiourea retained on the surface. A further heat treatment converted gradually amine nitrogen into pyridines/pyrroles and quaternary nitrogen, shifting the adsorption mechanism to rather specific interactions than a direct chemical reactivity. Carbons with few times less nitrogen than in their amine-modified counterparts, but in quaternary form and with the small amount of sulfur in thiophenic configurations, regardless the origin, worked as very efficient adsorbents of HCHO. Due to the modification of the carbon matrix electronic structure, resulting in a positive charge on carbon atoms in the vicinity of the heteroatoms incorporated to carbon rings, the density of specific adsorption centers on the surface in larger pores was significantly higher than that in ultramicropores. This markedly contributed to efficient utilization of pores/surface, where heteroatom can exist and where otherwise the dispersive adsorptions forces would be weak, for HCHO removal at ambient conditions.

Synthesis and characterization of Guargum Mandelic acid resin and its applications in industrial wastewater treatment

Presently, micro pollutants which occur in water resources worldwide are the main problematic issues causing hazardous effect on environment and harming human life. Polymeric resins are the effective adsorbents, which have properties like static chemical properties, high porosity and specific adsorbent sites. The new resin Guargum Mandelic Acid Resin (GMA), has been synthesized which is toxic free substance for the treatment of industrial waste water. Guargum Mandelic Acid Resin (GMA) has been used for the adsorption of heavy metal ions like Lead (Pb2+), Copper (Cu2+), Iron (Fe2+), Chromium (Cr²+), Zinc (Zn+²) etc. by batch and column method. The GMA resin was characterized by FTIR and SEM. In laboratory, experiments were performed at different pH range, concentration and time of contact.

Enhanced hybrid capacitive deionization performance by the mass balance of electrodes

The ion removal capacity of carbon based capacitive deionization (CDI) is limited by the double-layer mechanism. Replacing one electrode of the conventional carbon-based symmetric CDI with a battery-like ion insertion material to obtain hybrid capacitive deionization (HCDI) can significantly improve the adsorption capacity. Various ion insertion materials have been adopted for HCDI, however, how to optimize the performance of the HCDI system by matching the two electrodes with different ions removal mechanism remains challenging. In this work, a HCDI desalination cell was demonstrated by using NaTi2 (PO4)3/reduced graphene oxide composites (NTP-rGO-700) as the cathode and activated carbon (AC) as the anode. Based on the mass balance strategy of electrodes and the electrochemical behavior of hybrid capacitors with different AC:NTP-rGO-700 mass ratios, the HCDI desalination cell was assembled with the optimal AC:NTP-rGO-700 mass ratio of 2:1. At an operating voltage of 1.6 V and a current density of 125 mA·g−1, the specific adsorption capacity (SAC) of the HCDI cell can reach 51 mg·g−1 with an average salt adsorption rate (ASAR) of 2 mg·g−1·min−1, and the energy consumption (Em) is 136.53 kJ·mol−1. This work provides an efficient approach for developing high performance HCDI cell.

Selective adsorption and special recognition of roxarsone (ROX) from water by utilizing novel core-shell magnetic molecularly imprinted polymers

To eliminate environmental risk that induced from organoarsenic feed additive ROX, and enhance special selectivity and recognizability of this micro-polluted aromatic organoarsenicals compound in complex aqueous as well. Novel core-shell magnetic molecularly imprinted polymers (MMIPs) were successfully synthesized through the surface imprinting technology, which circumvented the drawbacks of traditional method such as the deep embedding of the imprinting sites and incomplete elution of the target molecule. Owing to its imprinting effect, the obtained MMIPs displayed excellent behavior and performance for ROX removal compared with magnetic non-imprinted polymers (MNIPs), the binding isotherms of ROX for both MMIPs and MNIPs were better fitted by Langmuir model, and two types of binding sites (specific and non-specific adsorption sites) existed on the surface of MMIPs. The removal efficiency of ROX by MMIPs remained unchanged along with a broad pH range (3.0–10.0), whereas pH seriously affected the ROX removal efficiency of MNIPs. The better uptake of ROX by MMIPs co-existed with competitive substances and two other organic/inorganic arsenic compounds (p-ASA/As(V)) confirmed the high binding selectivity and special recognizability for its target pollutant. Finally, the application in different spiked real water samples and continuous flow tests further demonstrated MMIPs were the promising candidates and of the potential application future to selectively remove this trace pollutant in different water bodies.

A nanocellulose molecularly imprinted membrane: Preparation, characterization and application in targeted separation of taxane 10-deacetylbaccatin III

Targeted separation of active phytochemicals is urgently needed in the natural medicine field. In this paper, due to the natural porosity and high biocompatibility of cellulose, a nanocellulose membrane combined with surface molecular imprinting was successfully prepared; the efficient nanocellulose-based molecular imprinted membrane (NC-MIM) provided good adsorption for the targeted separation of phytochemicals such as 10-deacetylbaccatin III (10-DAB), an essential intermediate in the synthesis of the anticancer drug paclitaxel. Through a series of characterization and adsorption experiments, the adsorption mechanism of NC-MIM was determined. At pH 8.0 and temperatures of 20 °C–40 °C, the maximum capacity of NC-MIM for adsorption of 10-DAB reached 66.90 mg g − 1, and the content of 10-DAB was dramatically increased 17.5-fold after adsorption. The specific adsorption results showed that NC-MIM had excellent capacity for targeted separation of 10-DAB from among taxane structural analogues. Even after ten cycles, NC-MIM demonstrated a remarkable adsorption capacity of 86.43%, thereby indicating exceptional selectivity and stability. The successful implementation of NC-MIM for green, safe, and efficient enrichment of phytochemicals from plants provides a promising new approach and valuable insights into its practical application.

Investigating the potential of using solid waste generated from stone cutting factories for phenol removal from wastewater: A study of adsorption kinetics and isotherms

Remarkably toxic, phenol requires efficient elimination from water. This study investigates the utilization of solid waste generated by stone-cutting factories for extracting phenol from wastewater. The solid waste underwent thermal treatment at 105 °C for 3 h for characterization. Batch adsorption experiments systematically assessed parameters like phenol concentration, adsorbent mass, contact time, temperature, and pH. Optimal removal transpired at pH 7.5, reaching equilibrium within 4 h. Phenol uptake equilibrium values were 8.1, 13.3, 16.2, 20.2, and 28.1 mg/g for initial concentrations of 50, 100, 150, 200, and 300 mg/L, respectively using 1 g of adsorbent at ambient temperature. The Langmuir model fit acceptably, yet the Freundlich model surpassed it. The most suitable kinetics model for phenol adsorption was the pseudo-second-order. The nature of the adsorption process was endothermic. Importantly, this study pioneers the promising application of solid waste generated from stone-cutting factories as an adsorbent material for effective phenol removal, offering a sustainable approach. Notably, no previous study has been conducted on phenol removal from wastewater using this specific adsorbent, rendering this work pivotal in exploring its potential. This solid waste presents an economical, readily available, and environmentally benign material for the adsorption process, expected to exhibit substantial adsorption capacity.

Targeted Removal of Galloylated Flavanols to Adjust Wine Astringency by Using Molecular Imprinting Technology.

Excessive galloylated flavanols not only cause instability in the wine but also lead to unbalanced astringency. Although clarification agents are always used to precipitate unstable tannins in wine, the non-specific adsorption of tannins results in the failure to precisely regulate the tannin composition of the wine. In this work, molecularly imprinted polymers (MIPs) with template molecules of galloylated flavanols were designed to specifically adsorb gallotannins to reduce wine astringency. The results showed that the "pores" on the surface of the MIPs are the structural basis for the specific adsorption of the target substances, and the adsorption process is a chemically driven single-molecule layer adsorption. Moreover, in the mono/oligomeric gallotannin-rich model solution, the adsorption of gallotannins by I-MIPs prepared as single template molecules reached 71.0%, and the adsorption capacity of MIPs for monomeric gallotannins was about 6.0 times higher than polymeric gallotannins. Given the lack of technology for the targeted adsorption of tannins from wine, this work explored the targeted modulation of wine astringency by using molecular imprinting techniques.

Enrichment and activation of cyano in cobalt hexacyanoferrate for specific recovery of ultra-low concentrations of platinum

Adsorption recovery of ultra-low concentrations (1 ppm) of platinum (Pt) was challenging due to the inferior sensitivity response and poor specific affinity between sorbents and target ions. Herein, enrichment and activation of the cyano group (CN) on cobalt hexacyanoferrate (CoHCF) were achieved by crystal facets engineering to capture Pt(Ⅱ) efficiently and specifically. The Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and density-functional theory (DFT) calculations results revealed that the activity and density of CN on the (220) facets were higher than that on the (200) facet. The Pt(Ⅱ) adsorption efficiency on the CN-enriched and -activated CoHCF (CoHCF(220)) reached 92.5%, which was 1.56 times higher than that on the original CoHCF (59.2%). The specific adsorption of Pt(Ⅱ) was driven by the coordination interaction between Fe-CN– and Pt, leading to the Pt(Ⅱ)-Pd(Ⅱ) separation efficiency attained 98.95% within 20 min. In addition, CoHCF(220) equipped with Pt(Ⅱ) could be further chemically reduced as a photocatalyst for hydrogen evolution. This study suggested an attractive strategy for the practical recovery of Pt(Ⅱ) and comprehensive utilization of ultra-low concentration Pt-containing wastewater.

Effects of mesoporous TiO2 with addition of V2O5 and rinsing with various solvents on the properties of dye-sensitized solar cells

Dye-sensitized solar cells (DSSC) have received much attention since they are simple, easily manufactured, inexpensive, and offer reasonable conversion efficiency. Mesoporous TiO2 with the addition of V2O5 nano-particles (0, 0.5, 1.0, 1.5 and 2.0 wt%) as a photoanode in DSSC have been successfully fabricated using a spin-coating method. Titanium tetrachloride (TiCl4) was used to synthesize a thin TiO2 blocking layer to enhance the performance of TiO2 photoanode in DSSC. After annealing treatment at 450 °C, the TiO2 blocking layer showed an amorphous structure. Performance was examined after soaking N719 dye and rinsing with five different solvents (ethanol, isopropanol, acetone, methanol, and diethyl ether). The results show that removing unanchored dye molecules using acetone solution can increase the specific surface area and dye adsorption amount of TiO2, resulting in good Jsc and photovoltaic efficiency. A conversion efficiency of 8.5% was achieved using fluorine doped tin oxide glass, a thin blocking layer, mixing 0.5 wt% V2O5 with mesoporous TiO2 and rinsing with an acetone solution.

Deposition behaviors of carboxyl-modified polystyrene nanoplastics with goethite in aquatic environment: Effects of solution chemistry and organic macromolecules

The ubiquitous nanoplastics (NPs) in the environment are emerging contaminants due to their risks to human health and ecosystems. The interaction between NPs and minerals determines the environmental and ecological risks of NPs. In this study, the deposition behaviors of carboxyl modified polystyrene nanoplastics (COOH-PSNPs) with goethite (α-FeOOH) were systematically investigated under various solution chemistry and organic macromolecules (OMs) conditions (i.e., pH, ionic type, humic acid (HA), sodium alginate (SA), and bovine serum albumin (BSA)). The study found that electrostatic interactions dominated the interaction between COOH-PSNPs and goethite. The deposition rates of COOH-PSNPs decreased with an increase in solution pH, due to the enhanced electrostatic repulsion by higher pH. Introducing cations or anions could compress the electrostatic double layers and compete for interaction sites on COOH-PSNPs and goethite, thereby reducing the deposition rates of COOH-PSNPs. The stabilization effects, which were positive with ions valence, followed the orders of NaCl ≈ KCl < CaCl2, NaNO3 ≈ NaCl < Na2SO4 < Na3PO4. Specific adsorption of SO42− or H2PO4− caused a potential reversal of goethite from positive to negative, leading to the electrostatic forces between COOH-PSNPs and goethite changed from attraction to repulsion, and thus significantly decreasing deposition of COOH-PSNPs. Organic macromolecules could markedly inhibit the deposition of COOH-PSNPs with goethite because of enhanced electrostatic repulsion, steric hindrance, and competition of surface binding sites. The ability for inhibiting the deposition of COOH-PSNPs followed the sequence of SA > HA > BSA, which was related to their structure (SA: linear, semi-flexible, HA: globular, semi-rigid, BSA: globular, with protein tertiary structure) and surface charge density (SA > HA > BSA). The results of this study highlight the complexity of the interactions between NPs and minerals under different environments and provide valuable insights in understanding transport mechanisms and environmental fate of nanoplastics in aquatic environments.

Zwitterionic peptides: Tunable next-generation stealth nanoparticle modifications.

Adsorption of proteins to nanoparticles (NPs), a complex process that results in a protein corona, is controlled by NP surface properties that define NP interactions in vivo. Efforts to control adsorbed protein quantity through surface modification have led to improvements in circulation time or biodistribution. Still, current approaches have yet to be identified to control adsorbed protein identities within the corona. Here, we report the development and characterization of diverse zwitterionic peptides (ZIPs) for NP anti-fouling surface functionalization with specific and controllable affinity for protein adsorption profiles defined by ZIP sequence. Through serum exposure of ZIP-conjugated NPs and proteomics analysis of the resulting corona, we determined that protein adsorption profiles depend not on the exact composition of the ZIPs but on the sequence and order of charges along the sequence (charge motif). These findings pave the way for developing tunable ZIPs to orchestrate specific ZIP-NP protein adsorption profiles as a function of ZIP charge motif to better control cell and tissue specificity and pharmacokinetics and provide new tools for investigating relationships between protein corona and biological function. Furthermore, overall ZIP diversity enabled by the diversity of amino acids may ameliorate adaptive immune responses.

Tannic acid purification from pomegranate peel via tannic acid imprinted particle-embedded cryogel column

Tannic acid (TA) is hydrolysable tannin found in the leaves and bark of many herbaceous and woody plants. Purification of TA is important due to its antibacterial, antihistaminic, antioxidant, antimutagenic and antitussive properties. In this study, 2-hydroxyethyl methacrylate-based TA-imprinted particle embedded cryogel (TA-MIP) was synthesized to purify TA from pomegranate peel. Furthermore, non-imprinted particle embedded cryogel (NIP) was synthesized to determine specific adsorption properties of TA-MIP, and control cryogel was synthesized without embedding procedure. The synthesized cryogel columns were characterized via scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, fourier-transform infrared spectroscopy, and swelling studies. Particle-embedding procedure resulted in a significantly higher specific surface area of particle-embedded columns (TA-MIP and NIP, 29 m2/g and 25 m2/g, respectively) than the specific surface area of control cryogel (9 m2/g). Adsorption studies were performed from aqueous solutions and maximum TA adsorption was found to be 34.4 mg/g for TA-MIP, 3.9 mg/g for NIP, and 2.8 mg/g for control cryogel. Within the scope of selectivity study, it was demonstrated that the synthesized columns have a high selectivity for TA against gallic acid (GA) and quercetin (QCT). Finally, purification of TA directly from pomegranate peel extract was studied and results were confirmed by HPLC. Furthermore, it has been proven that TA-MIP cryogel columns can be repeatedly used up to ten-times without any remarkable reduction in the TA adsorption amount.

Multivariate Data Analysis of Multisine Impedimetric Fingerprints in Electroanalysis of Biochemical Compounds

While Electrochemical Impedance Spectroscopy (EIS) is found as one of the most versatile tools of electrochemical characterization, it suffers a major drawback when the process in question is non-stationary. On the other hand, Dynamic Electrochemical Impedance Spectroscopy (DEIS) offers an ultra-fast measurement time. DEIS utilizes an approach where all the elementary components are superimposed as one multi-component perturbation signal, offering impedance spectra collection in seconds. This particular advantage allows for the effective use of DEIS in the monitoring of the adsorption processes in multiple fields, such as (bio)sensing, corrosion science, energy storage, or AFM-coupled impedance mapping.This presentation aims at highlighting the DEIS monitoring utility carried out with changes of an independent variable, such as adsorbate concentration or even under linear polarization sweep. Rapid and accurate determination of adsorption isotherms for green organic corrosion inhibitors or Michaelis-Menten constant for enzyme-based glucose (bio)sensors with DEIS operating in galvanostatic mode and under iDC = 0 were already established. When it comes to impedimetric macromolecular electroanalysis, measuring charge transfer resistance upon analyte adsorption is the most common approach. However, the detection may also base on other factors, such as adsorbed layer capacitance or even disturbance in frequency dispersion of capacitance. Most recently, DEIS under polarization sweep mode allowed us to obtain the unique fingerprint of the electric parameter changes, specific to studied macromolecules (such as DNA strings, viral proteins, RNA polymerase, and enzymes). To effectively use our approach DEIS is combined with multivariate data analysis (principal component analysis with partial least square regression). Multivariate data analysis processes large amounts of generated impedimetric data and defines analyte-sensitive conditions (DC polarization, AC amplitude, frequency range, etc.), which can be done just by using the raw data by the singular-value decomposition method to support the sensing mechanisms. The proposed approach neglects some of the reproducibility issues induced by non-specific adsorption and fouling and reveals the measurement conditions that offer the highest variation of studied parameters upon specific analyte adsorption. The authors acknowledge the financial support of these studies by the National Science Centre (Republic of Poland) under project 2020/37/B/ST7/03262.

(Invited) Probing the Specific Adsorption of Alkali Metal Cations on Au Electrodes Under CO2 Reduction

Electrolyte engineering has recently been recognized as an integral component in the design of electrode/electrolyte interfaces for electrocatalysis. In particular, alkali metal cations of the supporting electrolyte are known to influence electrocatalytic processes. A better understanding of these cation effects requires methods capable of probing the distribution of alkali metal cations in the electrochemical double layer under reaction conditions. However, the scarcity of experimental technique capable of probing alkali metal cations greatly hinders further advances in leveraging cation effects in electrolyte engineering. In this talk, we will discuss our novel spectroscopic approach for quantifying the surface coverage of specifically adsorbed alkali metal cations, that is, the cations that are in direct contact with the electrode and therefore most likely to influence electrocatalysis. The technique is based on the use of an organic cation, tetramethylammonium (methyl4N+), as a vibrational probe of the electrode/electrolyte interface in the presence of alkali metal cations. We will discuss how we use this approach to characterize the adsorption of alkali metal cation during CO2-to-CO conversion.

Reveal the Electrical Double Layer (EDL) in Zinc Battery Electrolytes with Electrocapillarity

The electrified interface between electrodes and electrolytes, aka, electrical double layer (EDL), resides at the heart of electrochemistry and exists universally in all electrochemical devices. It governs the kinetics and reversibility of all electrochemical processes, and predicts the interphase chemistries in advanced batteries. However, despite such importance, its understanding remains insufficient. While many theoretical models have been developed to predict EDL structure and to correlate key properties to the structures, so far there have been very rare direct experimental characterization, due to the limitations of existing techniques and the extreme elusiveness and sensitivity of the electrified interfaces.In this talk, I will discuss a modernized high-resolution electrocapillarity method, developed in my group. Applying this reborn electrocapillarity on a bivalent electrolyte of ZnCl2 and ZnSO4, we reveal the interfacial structure of Zn ion battery electrolytes in the absence and presence of anion specific adsorption and established the abnormal potential distribution across the interface due to anion adsorption and its effect on the kinetics of Zn ion deposition chemistry.

Machine learning screening based strategy for the synthesis of a molecularly imprinted ionic liquid polymer for specific adsorption of perfluorooctanoic acid

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant that poses a significant environmental threat due to its resistance to degradation in both aquatic and terrestrial environments. Ionic liquids (ILs) are a type of salt that is liquid at or near room temperature and have been widely used in separation science, as well as showing great potential in environmental applications. However, the large number and variety of ILs make them impractical to assess the suitability of all possible ILs for PFOA adsorption using purely experimental methods. To address this issue, a high-throughput machine learning method was employed in this study to screen more than a thousand ILs and identify the most appropriate molecular for designing IL based molecularly imprinted polymer (MIP) with high affinity and selectivity of PFOA. The synthesized MIP, (Vim)C3(L-Pro)@MIP, has been proven to effectively and specifically recognize and adsorb PFOA in water. It has a maximum adsorption capacity of 568.18 mg g−1 and removal efficiency of over 99%, making it a highly efficient and selective option for PFOA removal in environmental remediation applications. This study showcases the promising potential of integrating high-throughput computer screening with experimental verification in the initial stages of MIP material design and development. By doing so, it is possible to create MIP materials that can effectively remove various pollutants, and potentially extend to other IL doped materials and applications.