Mesoporous Silica Nanoparticles for the Treatment of Complex Bone Diseases: Bone Cancer, Bone Infection and Osteoporosis

Bone diseases, such as bone cancer, bone infection and osteoporosis, constitute a major issue for modern societies as a consequence of their progressive ageing. Even though these pathologies can be currently treated in the clinic, some of those treatments present drawbacks that may lead to severe complications. For instance, chemotherapy lacks great tumor tissue selectivity, affecting healthy and diseased tissues. In addition, the inappropriate use of antimicrobials is leading to the appearance of drug-resistant bacteria and persistent biofilms, rendering current antibiotics useless. Furthermore, current antiosteoporotic treatments present many side effects as a consequence of their poor bioavailability and the need to use higher doses. In view of the existing evidence, the encapsulation and selective delivery to the diseased tissues of the different therapeutic compounds seem highly convenient. In this sense, silica-based mesoporous nanoparticles offer great loading capacity within their pores, the possibility of modifying the surface to target the particles to the malignant areas and great biocompatibility. This manuscript is intended to be a comprehensive review of the available literature on complex bone diseases treated with silica-based mesoporous nanoparticles-the further development of which and eventual translation into the clinic could bring significant benefits for our future society.

Exploring functionalized titania for task specific application of efficient separation of trivalent f-block elements

Functionalized titania, obtained by grafting the dipicolinic acid functionality, was explored for task specific application of highly efficient separation of trivalent f-block elements.

The influence of hydrofluoric acid etching processes on the photocatalytic hydrogen evolution reaction using mesoporous silicon nanoparticles

H2 has been identified as one of the potential energy vectors that can provide a sustainable energy supply when produced through solar-driven water-splitting reaction. Si is the second most abundant element in the Earth's crust and can absorb a significant fraction of the solar spectrum while presenting little toxicity risk, making it an attractive material for photocatalytic H2 production. Hydrogen-terminated mesoporous Si (mp-Si) nanoparticles can be utilized to effectively drive the hydrogen evolution reaction using UV-to-visible light. In this work, the response of the photocatalytic activity of mp-Si nanoparticles to a series of HF acid treatments was investigated. A two-step magnesiothermic reduction method was used to prepare crystalline mp-Si nanoparticles with a specific surface area of 573 m2 g-1. The HF etching process was optimized as a function of the amount of acid added and the reaction time. The reaction time did not influence the H2 evolution rate substantially. However, the amount of HF used did have a significant effect on the photocatalytic activity. In the presence of ≥1.0 mL HF acid per 0.010 g of Si, morphological damage was observed using electron microscopy. N2 adsorption measurements indicated that the pore size and surface area were also altered. Solution-phase 19F{1H} NMR studies indicated the formation of SiF5- and SiF62- when larger volumes of HF were used. Both factors, morphological damage and the presence of byproducts in the pores, likely result in a lowering of the photocatalytic H2 evolution rate. Under the optimized HF treatment conditions (0.5 mL of HF per 0.010 g of Si), a H2 evolution rate of 1398 ± 30 μmol g-1 h-1 was observed.

Synthesis of Fe3O4@PVBC-TMT nanoparticles for the efficient removal of heavy metals ions

Core–shell magnetic Fe₃O₄@PVBC–TMT (Fe₃O₄@polyvinylbenzyl chloride–trithiocyanuric acid) nanoparticles containing trithiocyanuric acid groups were fabricated and employed for the fast removal of heavy metals from an aquatic environment. The morphology, structure and properties of Fe₃O₄@PVBC–TMT nanoparticles were characterized by a series of modern analytical tools. The adsorption behavior of the Fe₃O₄@PVBC–TMT nanoparticles for heavy metals ions in aqueous solutions was investigated by batch experiments. The maximum removal capacities of the Fe₃O₄@PVBC–TMT nanoparticles toward Mn²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Pb²⁺ ions were 127.4, 146.6, 180.5, 311.5, and 528.8 mg g⁻¹, respectively. Importantly, it is found that Pb²⁺ ions can be completely and quickly removed by the Fe₃O₄@PVBC–TMT nanoparticles. The equilibrium was established within 6 min, and the removal efficiencies were found to be 99.9%, 99.8% and 99.5% for Pb²⁺ ions at the initial concentrations of 100 mg L⁻¹, 200 mg L⁻¹ and 300 mg L⁻¹, respectively. It is hoped that the core–shell magnetic Fe₃O₄@PVBC–TMT nanoparticles may find application in wastewater treatment.

Core–shell Fe₃O₄@PVBC–TMT nanoparticles were fabricated and served as a valid magnetic adsorbent for the removal of heavy metals ions.

A sustainable ferromanganese biochar adsorbent for effective levofloxacin removal from aqueous medium

This present study reported the synthesis and characterization of a low-cost, environment friendly and high efficient biochar, ferromanganese modified biochar (Fe/Mn-BC) for the removal of levofloxacin (LEV) from aqueous medium. Fe/Mn-BC was synthesized through the facile co-precipitation of Fe, Mn with vinasse wastes and then pyrolysis under controlled conditions. The characterization of Fe/MnBC was analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction patterns (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman. Some influencing factors (e.g., pH, Fe/Mn-BC dosage, initial LEV concentration, ionic strength, contact time and temperature) were comprehensively investigated. The results manifested that the adsorption process of LEV onto Fe/Mn-BC was high pH dependence and the maximum adsorption capacity was achieved at pH 5. Moreover, the adsorption capacity of LEV was increased with increasing ionic strength. To gain a clearer perspective on the adsorption behavior of LEV onto Fe/Mn-BC, the adsorption kinetics and isotherms were also performed, revealing pseudo-second-order and Freundlich model had a better fitting effect. Reusability experiments indicated that Fe/Mn-BC could maintain a certain adsorption capacity for LEV after 5 recycles. Overall, this work showed that Fe/Mn-BC was an effective and promising adsorbent for eliminating LEV from aqueous medium.

Novel mesoporous organosilica nanoparticles with ferrocene group for efficient removal of contaminants from wastewater

Traditional method to functionalize mesoporous silica nanoparticles with organic groups for removal of contaminants from wastewater was surface modification. However, this surface modification could not cover the entire surface, leading to incomplete utilization of the high surface area of MSNs. In this work, we designed and prepared a novel inorganic-organic hybrid nanomaterial: ferrocene incorporated mesoporous organosilica nanoparticles (MONs). Owing to the mesoporous structure, large surface area and the ferrocene group in the framework, MONs could adsorb phosphate anion more efficiently with adsorption capacities up to 1299 mg/g than surface modified MSNs (SiO₂-Fe) (488 mg/g). Congo red (CR) and Pb²⁺ were also used as the model contaminants, and the results indicated that MONs is a superior absorbent comparing with ferrocene surface modified MSNs.

Recent advances in the application of silica nanostructures for highly improved water treatment: a review

The demand for high-quality safe and clean water supply has revolutionized water treatment technologies and become a most focused subject of environmental science. Water contamination generally marks the presence of numerous toxic and harmful substances. These contaminants such as heavy metals, organic and inorganic pollutants, oil wastes, and chemical dyes are discharged from various industrial effluents and domestic wastes. Among several water treatment technologies, the utilization of silica nanostructures has received considerable attention due to their stability, sustainability, and cost-effective properties. As such, this review outlines the latest innovative approaches for synthesis and application of silica nanostructures in water treatment, apart from exploring the gaps that limit their large-scale industrial application. In addition, future challenges for improved water remediation and water quality technologies are keenly discussed.

Design and analysis for the removal of active pharmaceutical residues from synthetic wastewater stream

The removal of three over-the-counter pharmaceuticals from aqueous solution using four different adsorbents was analyzed. To study the effect of infused pharmaceutical and adsorbent on the adsorption system, both the concentration of drug and adsorbent dosage were varied, with constant temperature and pressure at different contact time. Adsorption kinetics, isotherm models, and ANOVA allegorized a generic trend for pharmaceutical removal efficiency of the adsorbents that varied as follows: activated carbon > fly ash > bentonite > sugar cane bagasse ash. The Tempkin model appears to fit the isotherm data better than Freundlich and Langmuir. Correspondingly, the kinetic studies implied a pseudo-second-order fit, to understand the mechanism by which the solute accumulates on the surface of a solid and gets adsorbed to the surface via intra-particle diffusion. Furthermore, some special cases of removal tendencies were noted based on sorbate-sorbent interaction. Effectively, it was observed that at an adsorbent loading of 2 g and initial concentration of 0.2 mmol L^-1, bentonite, fly ash, and activated carbon were able to strip more than 80% of all pharmaceuticals from urine. A framework for the highest significance of the experiments was obtained using response surface methodology by the combination of ciprofloxacin-bentonite followed by paracetamol-activated carbon and ibuprofen-activated carbon. Quasi-Newton and Bayesian regression methods were implemented on Langmuir isotherm by designing the neural network for the batch adsorption experiments. Based on the numerical calculations and graphical representations, the proposed model leads to the result that error is minimized and the values are optimized for different pharmaceuticals such as paracetamol, ibuprofen, ciprofloxacin that can be removed from wastewater streams by locally available adsorbents. Graphical abstract.

Preparation of fluoropolymer materials with different porous morphologies by an emulsion template method using supercritical carbon dioxide as a medium

The choice of a suitable surfactant is key to the formation of a stable water-in-CO2 (W/C) or CO2-in-water (C/W) emulsion. It is even more critical in stabilization of the emulsion containing carbon dioxide (CO2). In this study, the successful preparation of W/C emulsion was achieved by using the amphiphilic block polymer poly(ethylene glycol) methyl ether-b-poly(trifluoroethyl methacrylate) (mPEG45-b-(TFEMA) n ) as a surfactant, in which CO2 was used as a solvent for the fluoromonomer, trifluoroethyl methacrylate (TFEMA). In the case of the W/C emulsion, CO2 and TFEMA were used as the continuous phase and water as the internal phase of the emulsion system. It has been found that in the length of the block polymer mPEG45-b-(TFEMA) n , the fluorine-containing chain end has a significant effect on the morphology of the polymer and the type of emulsion formed. The morphology of the polymer was observed by scanning electron microscopy which confirmed the type of emulsion formed. With the fluorine-containing end segment, the morphology of the polymer changes from a small hollow sphere in a large hollow sphere to a hollow spherical to a porous structure. Correspondingly, it could be concluded that the type of emulsion could go through the process from water-in-CO2-in-water-in-CO2 (W/C/W/C) emulsion to water-in-CO2-in-water (W/C/W) emulsion to water-in-CO2 (W/C) emulsion. Also, suitable co-surfactants were identified in this study. Investigations were also attempted to check the effect of the amount of surfactant, cross-linker and water/CO2 ratio on the type of emulsion formed as well as the morphology of the resultant polymer.

Solid phase extraction of pesticides from environmental waters using an MSU-1 mesoporous material and determination by UPLC-MS/MS

This paper describes the synthesis of a silica based MSU-1 mesoporous solid and its application as sorbent in solid-phase extraction to pre-concentrate thirteen pesticides of low-high polarity (methomyl, cymoxanil, carbofuran, monolinuron, isoproturon, methidathion, methiocarb, malathion, phosalone, diazinon, penconazole, neburon and chlorotoluron) in ground and river water. The synthesis was based in an H-bonding interaction assembling (I⁰N⁰) between two non-ionic components (the inorganic silica surface, I⁰ and the polyethylene oxide template, N⁰) by adding tetraethoxysilane to the non-ionic surfactant Brij®100, the latter previously dissolved in HCl 1 M. 50 mL water samples adjusted at pH= 3.5 were passed, at a flow rate of 5 mL/min, through a home-made cartridge containing 50 mg of MSU-1 sorbent, pre-conditioned with 5 mL of ultrapure water; then, the cartridge was washed with 5 mL of ultrapure water. Following elution with 5 mL of acetonitrile, the pesticides were determined by ultra performance liquid chromatography coupled to triple quadrupole-mass spectrometry. Two selected reaction monitoring transitions were monitored per compound, the most intense one being used for quantification and the second one for confirmation. Three points were used for identification, as established in the Directive 96/23/EC for LC-MS/MS analysis, which deals with confirmatory methods for organic residues and contaminants listed in the Group B (veterinary drugs and contaminants). Medium matrix effect (|20%|<ME<|50%|) was found for methiocarb and malathion, whereas diazinon and phosalone showed strong matrix effect (ME≥>|50%|). Therefore, the standard addition methodology was applied by adding an adequate amount of the pesticide standard mixture to the final sample extract. All pesticides were quantified using this approach for practical reasons, thus avoiding two different calibrations. The method quantification limit (MQL) of pesticides was 0.01 μg/L for all of them, except for diazinon (0.1 μg/L). Recoveries of the target pesticides at MQL and 0.25 µg/L concentration levels in blank river water were in the range 70.1-113.5% and 86.7-107.3%, respectively, with RSDs lower than 16.3% and 15.7%, respectively. Four ground water samples and three river water samples, taken from Almería (Spain), were analyzed by the proposed method and only phosalone at a concentration level of 0.05 µg/L was found in one river water sample.

Supramolecular Hybrid Material Based on Engineering Porphyrin Hosts for an Efficient Elimination of Lead(II) from Aquatic Medium

Porphyrins show great promise for future purification demands. This is largely due to their unique features as host binding molecules that can be modified at the synthetic level, and largely improved by their incorporation into inorganic based materials. In this study, we assessed the efficacy of a hybrid material obtained from the immobilization of 5,10,15,20-tetrakis(pentafluorophenyl)-porphyrin on silica surface to remove Pb(II), Cu(II), Cd(II), and Zn(II) ions from water. The new organic-inorganic hybrid adsorbent was fully characterized by adequate techniques and the results show that the hybrid exhibits good chemical and thermal stability. From batch assays, it was evaluated how the efficacy of the hybrid was affected by the pH, contact time, initial metal concentration, and temperature. The adsorption kinetic and isotherms showed to fit the recent developed fractal-like pseudo-second-order model and Langmuir–Freundlich model respectively. The highest adsorption capacities for Pb(II), Cu(II), Cd(II), and Zn(II) ions were 187.36, 125.17, 82.45, and 56.23 mg g⁻¹, respectively, at pH 6.0 and 25 °C. This study also shows that metal cations from real river water samples can be efficient removed in the presence of the new adsorbent material.

Multifunctional Binding Chemistry on Modified Graphene Composite for Selective and Highly Efficient Adsorption of Mercury

Engineering of multifunctional binding chemistry on graphene composites using thiol-ene click reaction for selective and highly efficient adsorption of mercury(II) is demonstrated. Graphene oxide (GO) is used as an initial material for covalent attachment of cysteamine molecules by thiol-ene click reaction on C═C groups to achieve a partially reduced graphene surface with multiple binding chemistry such as O, S, and N. Batch adsorption studies showed remarkable adsorption rate with only 1 mg L^-1 dosage of adsorbent used to remove 95% Hg (II) (∼1.5 mg L^-1) within 90 min. The high adsorption capacity of 169 ± 19 mg g^-1, high selectivity toward Hg in the presence of 30 times higher concentration of competing ions (Cd, Cu, Pb) and high regeneration ability (>97%) for five consecutive adsorption-desorption cycles were achieved. Comparative study with commercial activated carbon using spiked Hg (II) river water confirmed the high performance and potential of this adsorbent for real mercury remediation of environmental and drinking waters.

Adsorptive removal of methylene blue from aqueous solution using coal fly ash-derived mesoporous silica material

In the present work, coal fly ash-derived mesoporous silica material (CFA-MS) has been successfully fabricated without employing any extra silica source. The obtained CFA-MS was characterized by Fourier transform infrared spectroscopy, nitrogen adsorption–desorption measurement, powder X-ray diffraction and transmission electron microscopy. Nitrogen adsorption–desorption measurement disclosed that CFA-MS possesses Brunauer–Emmett–Teller-specific surface area of 497 m2·g−1 and pore volume of 0.49 cm3·g−1, respectively. Furthermore, CFA-MS was evaluated for the adsorptive removal of methylene blue from aqueous solution. Several influence parameters on the removal of methylene blue including contact time, pH, initial concentration and temperature were studied in detail. Moreover, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were employed for interpretation of the adsorption process, while the pseudo-first-order and pseudo-second-order kinetics equations were applied to investigate the adsorption kinetics. Results in the current work demonstrate that CFA-MS can be used as an efficient adsorbent for methylene blue removal.

Effect of Salinity on Silica Nanoparticle Adsorption Kinetics and Mechanisms for Fluid/Rock Interaction with Calcite

This study addresses the kinetics of silica nanoparticle adsorption on calcite from a solution at three salinities: deionized water (DIW), synthetic seawater (SSW), and low salinity water (LSW). The nanoparticle adsorption mechanisms and the effects on calcite dissolution are addressed. It was shown that nanoparticle adsorption was best described with the second-order-kinetic model and that silica nanoparticle adsorption reduced calcite dissolution. This was confirmed by measuring the Ca²⁺ ion concentration, the pH, and by estimating the amount of calcite dissolved. This is an important conclusion of this work, especially as LSW as an enhanced oil recovery technique is a candidate for use in chalk fields. Less formation damage/dissolution of chalk when silica nanoparticles are combined with LSW can lower the risk of reservoir subsidence. Intraparticle diffusion and the pseudo-second-order models, indicated a reduction in the adsorption rate with increasing nanoparticle concentration in LSW. This is explained by possible repulsive forces among the nanoparticles as they diffuse from the bulk fluid onto the calcite surface. Ion charges reduce the repulsion among the nanoparticles through shielding. However, an increasing nanoparticle concentration reduces the shielding efficiency by the ions. Estimates of the surface forces confirmed that nanoparticle–mineral interaction is less attractive in LSW as compared to SSW and DIW.

Rapid adsorption and enhanced removal of emodin and physcion by nano zirconium carbide

In this study, nano zirconium carbide (n-ZrC) was synthesized by preceramic polymers method, and it was used to adsorb emodin and physcion from solutions for the first time. The prepared material was characterized by various technologies. The adsorption experiment was carried out to investigate the emodin and physcion removal performance. The results indicate that the pseudo-second-order kinetic model and the Langmuir model correlated satisfactorily to the experimental data, and the thermodynamic parameters are also calculated. Especially, n-ZrC can remove >95% of emodin or physcion in a minute under the optimal conditions, it is the fastest adsorption rate compared to other commonly used adsorbents (commercial zirconium carbide, activated carbon, C18, PSA, GCB and florisil). The adsorption mechanism was discussed, which suggests that Van der Waals' forces are the primary driving power during the adsorption process. Moreover, n-ZrC is stable at different pH and it can be reused at least fifteen times.

An amphiphilic organosilicon framework (AOF): a new solid Pickering catalyst carrier

The amphiphilicity of the AOF carrier originates from the amphiphilic pyridine groups in the frameworks of the nanoparticles.

Novel and effective strategy of dual bis(trifluoromethylsulfonyl)imide imidazolium ionic liquid immobilized on periodic mesoporous organosilica for greener cycloaddition of carbon dioxide to epoxides

Novel periodic mesoporous organosilica supported ionic liquids were prepared, characterized and evaluated as catalysts for cycloaddition of CO₂ to epoxides.

General microemulsion synthesis of organic–inorganic hybrid hollow mesoporous silica spheres with enlarged pore size

General microemulsion synthesis of organic–inorganic hybrid hollow mesoporous silica spheres with enlarge pore size with different kinds of pore expanders.

Giant Microgels with CO2-Induced On-Off, Selective, and Recyclable Adsorption for Anionic Dyes

Adsorbents that are capable of controllable pollutants adsorption and release without secondary pollution are attractive in water treatment. Here, we propose eco-friendly CO₂ as a trigger to switch the charge states and collapse-expansion transition of giant microgels consisting of hydrophilic acrylamide and hydrophobic 2-(diethylamino)ethyl methacrylate and demonstrated the on-off, selective, and recyclable adsorption of anionic dyes on microgels under CO₂ stimulation. Apart from easy-handling separation from the water by a simple filtration process, the maximum adsorption capacity is as high as 821 mg g^-1, and the adsorption isotherms and kinetics obeyed Langmuir isotherm and the pseudo-second-order kinetics models, respectively. The anionic dye can also be separated from the mixture solution using CO₂-treated microgels. Moreover, a wastewater treatment prototype with microgel-packed column was fabricated. Under continuous flow condition, the dye was removed and recovered by alternative bubbling CO₂ and flushing with aqueous alkali (pH 12). Thus, this type of microgels with CO₂-induced protonation-deprotonation transition can serve as a cost-effective, environmentally friendly, and efficient adsorbent for water purification applications.

Removal of Pb2+ in Wastewater via Adsorption onto an Activated Carbon Produced from Winemaking Waste

This work describes the adsorption of Pb2+ in aqueous solution onto an activated carbon (AC) produced from winemaking waste (cluster stalks). After characterizing the AC using Fourier transform infrared spectroscopy (FTIR) and micro-Raman spectroscopy, the influence of different physico-chemical factors (stirring rate, temperature, pH, adsorbent concentration, etc.) on its capacity to adsorb Pb2+ was examined. Kinetic and thermodynamic studies showed that the adsorption of the Pb2+ follows a pseudo-second-order kinetic model and fits the Langmuir isotherm model, respectively. The maximum adsorption capacity of the AC was 58 mg/g at 288 K temperature and pH of 4. In conclusion, ACs made from waste cluster stalks could be successfully used to remove Pb2+ from polluted water.

Clay-Based Nanocomposites as Recyclable Adsorbent toward Hg(II) Capture: Experimental and Theoretical Understanding

Here, we report the development of inorganic-organic hybrid nanocomposites through selective modification of the negative outer surfaces of halloysite nanoclays with two different organosilanes having primary or secondary amine sites to be explored them as novel and cost-effective adsorbents for the extraction of toxic inorganic contaminants from aqueous solution. They possess excellent selectivity for the adsorption of mercury, which shows monolayer molecular adsorption over the nanocomposites. The adsorption kinetics of Hg(II) is very fast and follows pseudo-second-order model compared to pseudo-first-order model. A combined experimental and theoretical study demonstrated that Hg(II) uptake by these nanocomposites is highly favorable and spontaneous up to 40 °C, and beyond this temperature, the uptake capacity gradually reduced. Temperature-dependent adsorption study exhibits endothermicity at low temperature (≤40 °C) and exothermicity beyond 40 °C. pH-dependent adsorption study showed their high uptake capacity until pH 7, which reduced at alkaline pH. All of the nanocomposites hold excellent adsorption capacity even at low concentration of adsorbate, along with multicycle sorption capability. The outstanding adsorption capacity as well as the easy synthetic route to achieve these nanocomposites may attract researchers to develop low-cost adsorbents to capture toxic metals, which in turn regulate the permissible limit of these toxic metals in drinking water.

Polycyclic Aromatic Hydrocarbons Adsorption onto Graphene: A DFT and AIMD Study

Density functional theory (DFT) calculations and ab-initio molecular dynamics (AIMD) simulations were performed to understand graphene and its interaction with polycyclic aromatic hydrocarbons (PAHs) molecules. The adsorption energy was predicted to increase with the number of aromatic rings in the adsorbates, and linearly correlate with the hydrophobicity of PAHs. Additionally, the analysis of the electronic properties showed that PAHs behave as mild n-dopants and introduce electrons into graphene; but do not remarkably modify the band gap of graphene, indicating that the interaction between PAHs and graphene is physisorption. We have also discovered highly sensitive strain dependence on the adsorption strength of PAHs onto graphene surface. The AIMD simulation indicated that a sensitive and fast adsorption process of PAHs can be achieved by choosing graphene as the adsorbent. These findings are anticipated to shed light on the future development of graphene-based materials with potential applications in the capture and removal of persistent aromatic pollutants.

Fe3+-bis-ethylenediamine complex bridged periodic mesoporous organosilica for the efficient removal of arsenate and chromate

The direct removal of arsenate (AsO4 3−) and chromate (CrO4 2−) from water were achieved using a Fe3+-bis-ethylenediamine complex-bridged periodic mesoporous organosilica with a 20% organosilane content (Fe-EDPMO-20). The bridged Fe3+-bis-ethylenediamine complex was introduced to the pore wall of the PMO by combining the pre-complexation and co-condensation processes. N,N′-bis[3-(triethoxysilyl)propyl]ethylenediamine (TESEN) and tetramethyl orthosilicate (TMOS) as silica precursors were used with cetyltrimethylammonium bromide (CTABr) as a surfactant under basic conditions for the preparation of highly ordered Fe-EDPMO-20. Transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption measurements confirmed that the Fe-EDPMO-20 had an ordered hexagonal p6mm mesostructure. The material had a Brunauer-Emmett-Teller surface area of 734 m2 g−1, pore diameter of 2.6 nm, and pore volume of 0.61 cm3 g−1. UV-vis and X-ray photoelectron spectroscopy confirmed that Fe3+ was embedded in the coordination site by the nitrogen atoms from ethylenediamine. The adsorption efficiencies of arsenate and chromate ions by Fe-EDPMO-20 were examined as a function of pH, stirring time, amount of adsorbent, and initial concentration of metal ion solution. The maximum adsorption for arsenate and chromate were 156 and 102 mg g−1 within 6 and 24 h, respectively, at pH 4.

Well-defined functional mesoporous silica/polymer hybrids prepared by an ICAR ATRP technique integrated with bio-inspired polydopamine chemistry for lithium isotope separation

Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique. The evolution of the mesoporous silica/polymer hybrids during synthesis, in terms of morphology, structure, surface and porous properties, was detailed. And, parameters influencing the controlled growth of polymer chains in the ICAR ATRP system were studied. Taking advantage of the abundant epoxy groups in the PGMA platform, post-functionalization of the mesoporous silica/polymer hybrids by the covalent attachment of macrocyclic ligands for the adsorptive separation of lithium isotopes was realized. Adsorption behavior of the functionalized hybrids toward lithium ions was fully investigated, highlighting the good selectivity, and effects of temperature, solvent and counter ions. The ability for lithium isotope separation was evaluated. A higher separation factor could be obtained in systems with softer counter anions and lower polarity solvents. More importantly, due to the versatility of the ICAR ATRP technique, combined with the non-surface specific PDA chemistry, the methodology established in this work would provide new opportunities for the preparation of advanced organic-inorganic porous hybrids for broadened applications.

Large-scale preparation of a 3D patchy surface with dissimilar dendritic amphiphiles

We show here the first example of the large-scale surface decoration of a macroscopic and porous monolith with dissimilar micropatches. Branched polyethylenimine (PEI) is alkylated with poly(propylene glycol) (PPG), leading to a reverse-micelle-like dendritic amphiphile of PEI@PPG. Peralkylation and partial quaternization of the residual amino groups of PEI@PPG produces a cationic dendritic amphiphile of PEI-N⁺@PPG. The two dendritic amphiphiles jointly stabilize a water-in-oil high-internal-phase emulsion to prepare open-cellular monoliths of macroscopic size, with the monolith pore surface dictated by the cationic and neutral dendritic amphiphiles. The amino groups of the neutral amphiphile are further derivatized into anionic dithiocarbamates. The resulting monolith, along with the dissimilar functional patches on the surface, simultaneously eliminates multiple anionic and cationic micropollutants from water to very low residues, and affords the pH-triggered sequential release. Our strategy of using dissimilar dendritic amphiphiles rather than block copolymers as surface building blocks can confer the resulting surface with robust and predesigned microenvironments besides the conventional coacervate structure, and thus can afford more functions.

Macrocyclic ligand decorated ordered mesoporous silica with large-pore and short-channel characteristics for effective separation of lithium isotopes: synthesis, adsorptive behavior study and DFT modeling

Effective separation of lithium isotopes is of strategic value which attracts growing attention worldwide. This study reports a new class of macrocyclic ligand decorated ordered mesoporous silica (OMS) with large-pore and short-channel characteristics, which holds the potential to effectively separate lithium isotopes in aqueous solutions. Initially, a series of benzo-15-crown-5 (B15C5) derivatives containing different electron-donating or -withdrawing substituents were synthesized. Extractive separation of lithium isotopes in a liquid-liquid system was comparatively studied, highlighting the effect of the substituent, solvent, counter anion and temperature. The optimal NH₂-B15C5 ligands were then covalently anchored to a short-channel SBA-15 OMS precursor bearing alkyl halides via a post-modification protocol. Adsorptive separation of the lithium isotopes was fully investigated, combined with kinetics and thermodynamics analysis, and simulation by using classic adsorption isotherm models. The NH₂-B15C5 ligand functionalized OMSs exhibited selectivity to lithium ions against other alkali metal ions including K(i). Additionally, a more efficient separation of lithium isotopes could be obtained at a lower temperature in systems with softer counter anions and solvents with a lower dielectric constant. The highest value separation factor (α = 1.049 ± 0.002) was obtained in CF₃COOLi aqueous solution at 288.15 K. Moreover, theoretical computation based on the density functional theory (DFT) was performed to elucidate the complexation interactions between the macrocyclic ligands and lithium ions. A suggested mechanism involving an isotopic exchange equilibrium was proposed to describe the lithium isotope separation by the functionalized OMSs.

One-pot synthesis of a highly porous anionic hypercrosslinked polymer for ultrafast adsorption of organic pollutants

Ultrafast adsorption of organic pollutants in water was achieved with a highly porous anionic hypercrosslinked polymer as an adsorbent.

Facile preparation of porous organic copolymer based on triptycene and crown ether for efficient organic dye adsorption

The novel copolymer POP-TCE-15 displayed extraordinary capacity to adsorb organic dye from water.

Adsorption and biodegradation of dye in wastewater with Fe3O4@MIL-100 (Fe) core-shell bio-nanocomposites

Adsorption and improved biodegradation of dyes in wastewater was achieved with Fe₃O₄@MIL-100 core-shell bio-nanocomposites, which were prepared by a step-by-step strategy and attached to the surface of bacteria via zero-length carbodiimide chemistry. The Fe₃O₄@MIL-100 (Fe) nano-composite showed excellent dye adsorption properties and the overall dye removal process followed second-order kinetics. The dye AO10 was completely eliminated from solution by the combined effects of adsorption and biodegradation within 15 and 25 h from initial dye concentrations of 25 and 50 mg/L, respectively. The time to degrade the dye decreased from 11 h for the free microorganisms to 5 h for the bio-nanocomposite. The procedure was non-toxic, allowed for magnetic separation of the bio-nanocomposite from solution, and showed good cycling performance for the removal of dye. Hence, the strategy of surface-engineering bacteria shows great potential for the treatment of dyes from industrial effluents.

Facile surface-engineered polymeric absorbents for simultaneous adsorption and degradation of organic wastes

Polymeric absorbents were surface-engineered with photocatalysts for simultaneous adsorption and degradation of organic wastes in water using a facile Pickering emulsion polymerization method. This facile strategy not only overcome the low light energy utilization of traditional photocatalysts-polymer nanocomposites due to the core-shell structure, but also could convenient control the microstructure of the photocatalysts owing to the separated preparation procedure when compared to the direct growth method. Firstly, binary bismuth oxyhalide composed as BiOI_0.5Cl_0.5 was chosen to engineered polymeric absorbents due to its higher photodegradation efficiency especially. After the emulsification and polymerization process, BiOI_0.5Cl_0.5 acting as the stabilizer would be fixed on the surface of the functional polymeric absorbents to form PA@BiOI_0.5Cl_0.5. Batch experiments were lunched using phenol as the test substance, the results shown that PA@BiOI_0.5Cl_0.5 could remove phenol completely within a short time and could be reused without any treatments with a simultaneous adsorption and degradation process. Furthermore, polymeric absorbents were engineered with commercial TiO₂ to prove the generality of this strategy.