Organic Solvent-free Preparation Research Articles

Chelating Fabrics Prepared by an Organic Solvent-Free Process for Boron Removal from Water.

A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, while the attachment reaction was carried out by immersing the grafted fabric in the NMDG aqueous solution. The chelating capacity of the chelating fabric prepared by reaction in the NMDG aqueous solution without any additives reached 1.74 mmol/g, which further increased to above 2.0 mmol/g when surfactant and acid catalyst were added in the solution. The boron chelation of the chelating fabric was evaluated in a batch mode. Fourier transform infrared spectrophotometer (FTIR) was used to characterize the fabrics. The chelating fabric can quickly chelate boron from water to form a boron ester, and a high boron chelating ability close to 18.3 mg/g was achieved in the concentrated boron solution. The chelated boron can be eluted completely by HCl solution. The regeneration and stability of the chelating fabric were tested by 10 cycles of the chelation-elution operations. Considering the organic solvent-free preparation process and the high boron chelating performance, the chelating fabric is promising for the boron removal from water.

Organic Solvent-Free Preparation of Chitosan Nanofibers with High Specific Surface Charge and Their Application in Biomaterials.

The application of chitosan nanofibers in biological tissue-engineering materials has attracted wide attention. A novel and organic solvent-free method was developed for the fabrication of rootlike chitosan nanofibers (CSNFs) with diameters of 40-250 nm. This method includes three-step mechanical processing of swelling-beating-centrifugation or swelling-beating-homogenization. The obtained nanofibers showed high yields (>95%) and positive specific surface charges (up to +375 μeq/g) and could be uniformly dispersed in the aqueous phase. The unique fiber shape and the good length-to-diameter ratio of CSNFs endowed chitosan nanofiber paper (CSNFP) products with excellent mechanical properties, and the wet tensile strength of the CSNFPs was nearly five times higher than common chitosan films. In addition, the calvaria-derived preosteoblastic cells exhibited a higher adherence efficiency and proliferation on CSNFP than on chitosan films. The chitosan nanofiber scaffold products also benefited the attachment of preosteoblastic cells and allowed them to grow in three dimensions. This method has significant industrial potential for the industrialization of chitosan nanofibers, which may have broad applications in various biomaterials.

Organic solvent-free preparation of keratin nanoparticles as doxorubicin carriers for antitumour activity

Doxorubicin is one of the most effective chemotherapeutic agents for the treatment of several neoplastic conditions, such as leukemia, neuroblastoma, soft tissue and bone sarcomas, breast cancer, ovarian cancer and others. However, its clinical application is limited by cardiotoxicity, such as cardiomyopathy, that once developed carries a poor prognosis and is frequently fatal. The controlled release of doxorubicin by means of a smart carrier is a strategy to overcome the aforementioned drawback. Herein, doxorubicin/keratin nanoparticles were prepared by loading the drug through ionic gelation and aggregation methods, without using cross linkers, organic solvents neither surfactants. Both methodologies afford nanoparticles with yields up to 100 wt%, depending on the loading amount of doxorubicin. Although aggregation yield smaller nanoparticles (≈100 nm), ionic gelation allows a higher drug loading (up to 30 wt%,). More importantly, nanoparticles obtained through this procedure display a pH-responsive release of the drug: indeed Peppas-Salhin model suggests that, the doxorubicin release mechanism is predominantly controlled by diffusion at pH 7.4 and by protein swelling at pH 5.Moreover, nanoparticles prepared by ionic gelation resulted in more efficient cell killing of MDA-MB-231 and MCF-7 breast cancer cells than those prepared by aggregation. Based on the herein presented preliminary results, ionic gelation emerges as a promising approach for the preparation of keratin-based doxorubicin nanocarriers for cancer therapy, that is worth to further investigate.

Organic solvent-free preparation of electrolyte membranes with high proton conductivity using aromatic hydrocarbon polymers and small cross-linker molecules

We prepared proton exchange membranes of sulfonated poly(phenylsulfone) [SPPSU] cross-linked with ethylene glycol (EG) or glycerol (GL). The cross-linking reaction was performed in an SPPSU aqueous solution including 0–12 molecules/repeating unit; R.U. of the cross-linker at 180–200°C to afford water-insoluble SPPSU membranes even in boiling H2O. The characteristic properties of the SPPSU membranes, such as the number of cation exchange sites, water retention abilities, mechanical properties, and proton conductivities, can be easily optimized by selecting the amount and type of cross-linkers and the reaction temperature. The SPPSU membranes had tensile strengths of up to 43.5MPa, moduli of up to 1.9GPa, and elongations at break of up to 30.2%. An SPPSU membrane prepared at 180°C using EG as a cross-linker exhibited a maximum proton conductivity of 0.23S/cm at 120°C and 90% relative humidity (RH), and the value remained at 0.11S/cm even at 40°C. A maximum residual weight of 98% was achieved for SPPSU membranes prepared at 200°C using GL as the cross-linker under oxidation conditions at 80°C for 1h, and they exhibited good chemical stability.

A novel and organic solvent-free preparation of solid lipid nanoparticles using natural biopolymers as emulsifier and stabilizer

In this work, a new and novel organic solvent-free and synthetic surfactant-free method was reported to fabricate stable solid lipid nanoparticles (SLNs) from stearic acid, sodium caseinate (NaCas) and pectin, as well as water. Melted stearic acid was directly emulsified into an aqueous phase containing NaCas and pectin, followed by pH adjustment and thermal treatment to induce the formation of a compact and dense polymeric coating which stabilized SLNs. The preparation procedures and formulations were comprehensively optimized. The inter- and intra-molecular interactions among three ingredients were characterized by fluorescence and Fourier transform infrared spectroscopies. The stability of as-prepared SLNs was evaluated under simulated gastrointestinal conditions, and compared with traditional SLNs prepared with organic solvents. Our results revealed that the SLNs prepared from this organic solvent-free method had superior physicochemical properties over the traditional SLNs, including smaller size and better stability. Furthermore, redispersible SLNs powders were obtained by nano spray drying, but only the SLNs prepared by organic solvent-free method had sub-micron scale, uniform and spherical morphology. The organic solvent-free preparation method was proved to be a promising approach to prepare stable and uniform SLNs for potential oral delivery applications.

Crosslinked PVA-based hybrid membranes containing di-sulfonic acid groups for alkali recovery

Hybrid cation exchange membranes (CEMs) are prepared from polyvinyl alcohol (PVA), 3-mercaptopropyltriethoxysilane (MPTES) and benzaldehyde disulfonic acid disodium salt (BADSANa), which contains several functional groups like –OH, –SH/ –Si(OC2H5)3 and –SO3Na/ –CHO, etc. The availability of –CHO and –Si(OC2H5)3 groups are of immense importance as they can be easily cross-linked with PVA–OH groups through the acetal and sol-gel reaction. The -SH groups are further oxidized into the –SO3H groups in the presence of Fenton’s reagent or ozone to make the membrane matrix charged. It has been observed that membrane hydrophilicity and ion exchange capacities gradually increase with the dosage of BADSANa and MPTES. The tensile strength of prepared membranes is in the range of 5.8–30.9 MPa while the elongation at break (Eb) of 118.9–447.2%. The short-term thermal stability is ranged between 165 and 275 °C. The alkali resistance is acceptable at room temperature. Diffusion dialysis (DD) process shows that if the prepared membranes are oxidized by Fenton’s reagent, the dialysis coefficients of NaOH (UOH) in NaOH /NaAlO2 solution are in the range of 2.8–23.4 mm/h along with the separation factors (S) in between 4.6 and 20.0. The optimized membrane (M6B2-F) has both the highest S value of 20.0 and UOH as 23.4 mm/h. The similar separation performance can be achieved if the membranes are oxidized by ozone instead of Fenton’s reagent. The ozone oxidation, the organic solvent free preparation, and the favorable DD performances may provide new clues for designing new cation exchange hybrid membranes for alkali recovery.

The progression of Al-based metal-organic frameworks – From academic research to industrial production and applications

Al-based metal–organic frameworks (Al-MOFs) were first prepared and intensively studied by Férey and co-workers. They synthesized and characterized various new structures (e.g. MIL-53, MIL-96, MIL-100, MIL-110). In parallel, BASF SE developed an own portfolio of MOFs. The synthesis for one of these Al-MOFs (Basolite A520) has recently been optimized to allow for organic solvent-free preparation. Basolite A520 can now be synthesized in a water-based route that has already led to ton-scale production. Thereby the Al-MOF is industrially produced via both an economic and environmentally compatible process. This reliable access together with their adsorption properties paves the way to the broad application of MOFs. The latter is driven by the current global megatrends that require innovative applications by high potential materials.

Photocatalytic oxidation of acetaldehyde with oxygen on TiO 2/ZSM-5 photocatalysts: Effect of hydrophobicity of zeolites

TiO 2 photocatalysts hybridized with ZSM-5 were prepared by the impregnation of (NH 4) 2[TiO(C 2O 4) 2] aqueous solution. This is one of the most ideal green processes in establishing TiO 2 photocatalysts because of an organic solvent-free preparation method. The highly hydrophobic H-ZSM-5 with low Al 2O 3 content was effective as an adsorbent for acetaldehyde molecules. These results suggest the close relationship between the hydrophobicity of the zeolite and the high photocatalytic reactivity of TiO 2 prepared on zeolites compared with unloaded TiO 2 catalysts. However, acetaldehyde molecules were strongly trapped on the Na + sites of ZSM-5 and their efficient diffusion onto the TiO 2 sites was inhibited, resulting in low photocatalytic reactivity. The photocatalytic oxidation of acetaldehyde over TiO 2/ZSM-5 was improved in the coexistence of H 2O vapor. The role of the H 2O molecules was estimated to be the efficient formation of OH radicals and the prevention of strong adsorption of acetaldehyde on the TiO 2 sites.

酸化チタン／ＺＳＭ‐５ゼオライト光触媒によるアセトアルデヒドの完全酸化分解反応

TiO2 hybridized with ZSM-5 zeolites were prepared by the impregnation of (NH4)2[TiO(C2O4)2] aqueous solution. This is one of the most ideal green processes in establishing TiO2 photocatalysts because of an organic solvent-free preparation method. The highly hydrophobic H-ZSM-5 having low Al2O3 content was effective as an adsorbent for acetaldehyde. On the other hand, acetaldehyde molecules were strongly trapped on the Na+ sites of ZSM-5 and their efficient diffusion onto the TiO2 sites was inhibited. These results suggest the close relationship between the interaction of reactant with zeolite surfaces and the photocatalytic reactivity of TiO2 prepared on the zeolites as compared to unloaded TiO2 catalysts. The photocatalytic oxidation of acetaldehyde on TiO2/ZSM-5 was improved in the presence of H2O vapor.