Development of ion-imprinted polymers for the selective extraction of Cu(II) ions in environmental waters

Several ion-imprinted polymers (IIPs) were synthesized via bulk polymerization with Cu(II) as template ion, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinking agent, and azobisisobutyronitrile as initiator in acetonitrile or methanol as porogen solvent. Non-imprinted polymers (NIPs) were similarly synthesized but without Cu(II). After grounding and sieving, the template ions were removed from IIPs particles through several cycles of elimination in 3 M HCl. All NIPs were equally subjected to this acid treatment with the exception of one NIP, called unwashed NIP. The resulting IIP/NIP particles were packed in solid phase extraction (SPE) cartridges for characterization. The SPE protocol was designed by optimizing a washing step following the sample percolation to eliminate potential interfering ions prior to the elution of Cu(II), all fractions analyzed by inductively coupled plasma mass spectrometry. The best IIP showed a high specificity (recovery of Cu(II) vs. interfering ions) and a good selectivity (retention on IIP vs. NIP). Its adsorption capacity was determined to be 63 μg g^-1. Then, a volume of 50 mL was percolated with 30 mg of IIP, thus giving rise to an enrichment factor of 24. Finally, applications to real samples (mineral and sea waters) were successfully performed. In addition, Brunauer-Emmett-Teller analyses showed that the surface area of the washed NIP was almost double that of the unwashed one (140.70 vs. 74.49 m² g^-1), demonstrating for the first time that the post-treatment of a NIP after its synthesis may have a significant impact on its porous structure, and thus need to be more precisely detailed by authors in the future papers.

Assessment soil cadmium and copper toxicity on barley growth and the influencing soil properties in subtropical agricultural soils

Evaluation joint cadmium (Cd) and copper (Cu) phytotoxicity in wide range of subtropical agricultural soils is highly vital for phytoremediation of soils contaminated with Cd and Cu. In this study, barley root elongation assays were performed in 30 representative soils in response to single and combined Cd and Cu inhibition. The single Cd caused nearly 50% inhibition of barley root elongation, and Cu induced more than 50% inhibition in most soils. Mixed Cd + Cu caused significant inhibition on barley growth with average relative root elongation values of 20.0% and 30.4% in soil with a pH < 7 and pH > 7, respectively. An antagonistic interaction was evaluated in combined Cd + Cu toxicity, which was strong in soils containing low soluble Cu and Cd contents. Soil pH was the controlling factor in predicting single and mixed Cd and Cu phytotoxicity, which could explain 44% and 46% variation of single Cd and Cu toxicity, respectively. Soil organic carbon and effective cation exchange capacity were another important factor positively influencing metal toxicity, which further improved empirical prediction models accuracy, with determined coefficient (r²) values of 0.44-0.84. These results provide a theoretical basis for soils Cd and Cu pollution control.

Synthesis process and adsorption performance of temperature-sensitive ion-imprinted porous microspheres (ReO4−-TIIM) for the selective separation of ReO4−

The adsorption–desorption process of imprinted microspheres is controlled by changing the temperature conditions of the external environment.

Dual-Functional Monomer MIPs and Their Comparison to Mono-Functional Monomer MIPs for SPE and as Sensors

A molecularly imprinted polymer (MIP) is a synthetic polymer that has characteristics such as natural receptors which are able to interact and bind to a specific molecule that is used as a template in the MIP polymerization process. MIPs have been widely developed because of the need for more selective, effective, and efficient methods for sample preparation, identification, isolation, and separation. The MIP compositions consist of a template, monomer, crosslinker, initiator, and porogenic solvent. Generally, MIPs are only synthesized using one type of monomer (mono-functional monomer); however, along with the development of MIPs, MIPs began to be synthesized using two types of monomers to improve the performance of MIPs. MIPs used for identification, separation, and molecular analysis have the most applications in solid-phase extraction (SPE) and as biochemical sensors. Until now, no review article has discussed the various studies carried out in recent years in relation to the synthesis of dual-functional monomer MIPs. This review is necessary, as an improvement in the performance of MIPs still needs to be explored, and a dual-functional monomer strategy is one way of overcoming the current performance limitations. In this review article, we discuss the techniques commonly used in the synthesis of dual-functional monomer MIPs, and the use of dual-functional monomer MIPs as sorbents in the MI-SPE method and as detection elements in biochemical sensors. The application of dual-functional monomer MIPs showed better selectivity and adsorption capacity in these areas when compared to mono-functional monomer MIPs. However, the combination of functional monomers must be selected properly, in order to achieve an effective synergistic effect and produce the ideal MIP characteristics. Therefore, studies regarding the synergistic effect of the MIP combination still need to be carried out to obtain MIPs with superior characteristics.

Co-precipitation polymerization of dual functional monomers and polystyrene-co-divinylbenzene for ciprofloxacin imprinted polymer preparation

Novel ciprofloxacin composite imprinted materials are synthesized by using co-precipitation polymerization of dual functional monomers (methacrylic acid and 2-vinylpyridine) and polystyrene-co-divinylbenzene. The intermolecular interactions between monomers and template are evaluated by molecular modeling analysis. The physicochemical properties of the obtained polymers are characterized using FT-IR, TGA, and SEM. Batch adsorption experiments are used to investigate adsorption properties (kinetic, pH, and isotherm). These polymers are employed to prepare the solid phase extraction cartridges, and their extraction performances are analyzed by the HPLC-UV method. DFT calculations indicate that hydrogen bonding and π−π stacking are the driving forces for the formation of selective rebinding sites. The obtained polymers exhibit excellent adsorption properties, including fast kinetics and high adsorption capacity (up to 10.28 mg g⁻¹) with an imprinted factor of 2.55. The Scatchard analysis indicates the presence of specific high-affinity adsorption sites on the imprinted polymer. These absorbents are employed to extract CIP in river water with recoveries in the range of 65.97–119.26% and the relative standard deviation of 3.59–14.01%. Furthermore, the used cartridges could be reused at least eight times without decreasing their initial adsorption capacity.

Ciprofloxacin imprinted polymers were prepared using co-precipitation polymerization of methacrylic acid, 2-vinylpyridine and polystyrene-co-divinylbenzene.

Fabrication of nickel-tagged magnetic imprinted polymeric network for the selective extraction of Ni(II) from the real aqueous samples

A new nickel ion, magnetic imprinted polymer was fabricated through the precipitation polymerization process, using amine-functionalized silica-capped iron oxide particles as a core material, and 4-vinyl pyridine as complexing agent methacrylic acid as functional monomer. The resulted magnetic adsorbent was employed to eliminate toxic Ni²⁺ ions from industrial wastewater. The different parameters were optimized, such as pH, shaking speed, and adsorbent dose, to obtain the maximum adsorption capacity. The synthesized material showed high selectivity coefficient for Ni⁺² ions in the presence of other competitive ions and followed pseudo-second-order kinetics and Langmuir isotherm. A good adsorption capacity of 158.73 mg g^-1 was obtained at optimized pH 6 in the concentration of 5 mg L^-1 nickel ions aqueous solution. The limit of detection, quantification, and the percent relative standard deviation was found to be 0.58, 1.93, and 3.4%. This proves the excellent performance of prepared magnetic Ni(II) ion-imprinted polymer for selective detoxification of Ni²⁺ ions from real aqueous samples. Due to tunable magnetic properties, the prepared MMIPs are highly selective and sensitive and highly porous in nature; due to excellent magnetic properties, there is no need for centrifugation. Just use external magnetic field, it has good reusability. Showing preparation of Ni (II) imprinted magnetic polymer.

Study on Synthesis and Adsorption Properties of ReO4 - Ion-Imprinted Polymer

In this work, an ion imprinted polymer (ReO₄ ^--IIP) of the perrhenate ion based on acrylamide (AM) and acrylic acid (AA) was prepared by solution polymerization using ReO₄ ^- as a template ion, N,N-methylenebisacrylamide (NMBA) as cross-linkers, hydrogen peroxide-vitamin C (H₂O₂-Vc) as an initiator, and a mixed solution of water (H₂O) and methanol (CH₃OH) with volume ratio v(H₂O)/v(CH₃OH) = 3:7 as a solvent. During the process of synthesis condition investigation and optimization, the adsorption capacity (Q) and the separation degree (R) in the equimolar concentration mixture solutions of NH₄ReO₄ and KMnO₄ were adopted as indexes, and the obtained optimal conditions were as follows: the molar ratios of NMBA, NH₄ReO₄, AA, H₂O₂, and Vc to AM were 5.73, 0.052, 1.29, 0.02, and 0.003, and the temperature and time of polymerization were 40 °C and 28 h, respectively. Under optimal conditions, the sample with indexes, Q and R of 0.064 mmol/g and 3.20, were harvested. What is more, a further reusability study found that good adsorption selectivity was maintained after repeating the experiment 9 times. Taking the non-IP prepared under the same conditions as a control, Fourier transform infrared spectroscopy, transmission electron microscopy, and Brunauer Emmett Teller were used to characterize the structure of the ReO₄ ^--IIP prepared under the optimal conditions. Finally, the kinetic study results showed that the zero-order kinetic model could better describe the adsorption process. The thermodynamic study results showed that the Langmuir model was more suitable for describing the isotherm adsorption process of the IIP.

Phytotoxicity of Cu2+ and Cd2+ to the roots of four different wheat cultivars as related to charge properties and chemical forms of the metals on whole plant roots

The relationship between the chemical forms of Cu²⁺ and Cd²⁺ adsorbed on the roots of different wheat cultivars and their phytotoxic effects on the plants were investigated. The wheat varieties Dunmaiwang (DMW), Tekang 6 (TK6), Zhongmai895 (ZM895), and Chaojixiaomai (AK68) were used. The zeta potentials of wheat roots, measured by the streaming potential method, were used to characterize root charge properties. Results indicated that the changes in zeta potential at pH 4.01-6.61 were 14.7, 15.53, 13.01, and 12.06 mV for ZM895, AK68, DMW, and TK6, respectively. The negative charge and functional groups on ZM895 and AK68 roots were greater than on DMW and TK6 roots, which led to more exchangeable and complexed Cu²⁺ and Cd²⁺ on ZM895 and AK68 roots and increased Cu²⁺ and Cd²⁺ toxicity compared to DMW and TK6. Coexisting cations, such as Ca²⁺, Mg²⁺, K⁺, and NH₄⁺, alleviated Cu²⁺ and Cd²⁺ toxicity to wheat roots through competition for adsorption sites on the roots, which decreased exchangeable and complexed Cu²⁺ and Cd²⁺ on wheat roots. The Ca²⁺ and Mg²⁺ were most effective in alleviating heavy metal toxicity and they decreased exchangeable Cu²⁺ on AK68 roots by 39.14% and 47.82%, and exchangeable Cd²⁺ by 8.51% and 28.23%, respectively.

Modeling of pollutant distribution based on mobile sensor networks

Pollution monitoring based on wireless sensor networks is becoming highly attractive. This paper presents an effective pollutant distribution modeling approach using a mobile sensor network. As for mobile nodes, energy consumption and link quality between nodes are two key factors. In the proposed approach, we present an autonomous sensing model and an energy-driven motion control scheme, which can make a good trade-off between energy efficiency and modeling accuracy. A comprehensive set of simulations demonstrate that our approach can model the pollutant distribution with less iteration times and higher accuracy. In particular, even for a relatively complex concentration field, the similarity between the reconstructed model and the pollutant distribution can reach 95% through about 20 iterations using 25 mobile sensor nodes. Moreover, we validated the feasibility of the proposed approach through an actual monitoring of water pollutant distribution.

An asynchronous-alternating merging-zone flow-injection gold nanoparticles probe method for determination of anti-diabetic pioglitazone hydrochloride medicine

A new method was established on the basis of coloration of gold nanoparticles by pioglitazone hydrochloride in acidic media.

Comparison study on separation of morin: ultrasound assisted molecularly imprinted polymeric nanoparticles-solid phase extractionversussolidification of floating organic-drop assisted dispersive liquid–liquid microextraction

A comparison study between SPE-MIP-NPs and SFOD-DLLME was presented for separation and preconcentration of morin from aqueous media.