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The conventional liquid electrolytes (LEs) have a high level of ionic conductivity; however, they often suffer from the poor processability and safety risks of potential leakage. Although solid-state electrolytes (SSEs) can solve these inherent problems of LEs, the ionic conductivity of most SSEs is several magnitudes lower than these of LEs. Herein, we report a novel strategy by building liquid ion-transport channels in a solid framework and prepared an electrolyte-locked separator (ELS) using a collagen fiber membrane (CFm). The liquid electrolyte was primarily infiltrated in the smaller voids of CFm, and its ionic conductivity could attain to 9.0 × 10−3 S cm−1 when the electrolyte absorption (EA) reached up to 112.0%. After centrifuging treatment, the electrolyte retentions (ER) and ionic conductivities of ELS were 108.93% and 8.37 × 10−3 S cm−1, respectively, which were much higher than those of commercial cellulose separator (CS), exerting excellent liquid-locking performances. In particular, the electrical double-layer capacitors (EDLC) assembled by ELS or CS were characterized and exhibited similar electrochemical performance, demonstrating the satisfactory ability and applicability of ELS for commercial use. In addition, the ELS-based EDLC exhibited favorable flexibility with relative lower loss of capacitance under different angles of bending.

A novel hierarchically fibrous solid acid catalyst was facilely prepared by supporting Keggin-type phosphotungstic acid (HPW) on fibrous substrate of mesoporous TiO2-Al2O3 binary oxide nanofiber bundles. The acid strength and specific surface area were rationally tuned by changing the composition of TiO2-Al2O3 nanofiber bundles. When applied in fructose dehydration to prepare 5-hydroxymethylfurfural (5-HMF) using DMSO as the solvent, the fibrous HPW/TiO2-Al2O3 catalyst exhibited high catalytic activity (80.3%), selectivity (89.3%) and stability during the cycles. Our results demonstrated a promising and facile strategy for developing highly active and recyclable solid acid catalysts.

Because of their low-cost and high bacterial interception efficiency, large-scale membrane separation technologies like microfiltration (MF) have been widely implemented for water disinfection. However, lack of antibacterial ability and low sustainability are two major drawbacks of most petroleum-based MF membranes, which are normally associated with hazardous issues including biofouling and nonbiodegradable waste. In this work, abundant animal hides, which are by-products of the meat processing industry, were proposed as raw materials to fabricate a sustainable MF membrane due to their natural, hierarchical, and renewable collagen fibrous network (CFN) with inherent biodegradability. After the removal of non-collagen compositions from animal hides, such as hair and fat, through a facile pretreating process base on green chemistry principles, a thin CFN based membrane (CFN-M) with a similar micropore size to that of commercial MF membranes could be produced. Furthermore, inspired by conventional leather tanning technology, tannic acids (TA) were selected as plant polyphenol tanning agent to modify collagen fibers based on tanning chemistry to improve the thermal stability of CFN-M. Moreover, the TA cross-linked CFN-M (TA@CFN-M) exhibited excellent antibacterial properties due to the production of reactive oxygen species (ROS) by the catechol functional group. The resulting TA@CFN-M achieved99.9% water disinfection efficiency with a flux of ∼150 L m

The resource utilization of distillers' grains (DGs) is an essential issue for the sustainable development of Chinese bai jiu industry. In this study, metal oxide (MxOy, M=Mg, Al and Fe) loaded biochar (M BC) was prepared by using DGs for the production of novel adsorption/release materials for phosphate (P). The results indicated that the P adsorption capacity of Mg-BC, Al-BC and Fe-BC were as high as 14.74, 8.06 and 14.51 mg P/g, respectively. XPS and FTIR analysis demonstrated that the adsorption mechanism of M BC for P included electrostatic attraction, hydrogen bonding, ion exchange, precipitation and ligand exchange. The release of P from M-BC+P could be controlled by low molecular weight organic acids (LMWOAs), which were affected by the loaded metal oxides on the biochar. The release of P from Mg-BC+P was higher than 70 % after 7 days, which was about 60 % if Al-BC+P was used. Thus, M-BC+P can be used as a high-performance controlled release phosphate fertilizer, providing a promising value-added application approach for the bai jiu distillers' grains.

Highly efficient removal of bilirubin from blood by hemoperfusion for liver failure therapy remains a great challenge in the clinical field due to the unsatisfied biocompatibility of non-biological materials and the slow adsorption kinetics of currently used bilirubin adsorbents. Here, inspired by the natural collagen-supported multiscale structures of the liver for bilirubin removal, a natural collagen-based artificial liver, named ColAL, was successfully constructed via a biomimetic synthetic strategy. ColAL exhibited a record-high adsorption capacity of 102.32 mg g−1 for bilirubin in the presence of 40.0 g L−1 bovine serum albumin. The ColAL also presented excellent bilirubin adsorption capacity in the complex serum. Importantly, the total bilirubin (TBIL) removal rate was higher than 69.17% and the direct bilirubin (DBIL) removal rate was 75.31% by immersing the ColAL in ex vivo blood samples. No damages were observed in the major organs after the injection of ColAL extract solution subcutaneously in vivo, indicating high biocompatibility and biostability of these natural collagen-based materials. This facile approach provides a new avenue to develop collagen-based high-performance hemoperfusion adsorbent for the removal of bilirubin, showing great promise to the translational therapy of hyperbilirubinemia.

The antioxidant activity in vivo and biological safety of a novel antioxidant peptide from bovine hair hydrolysates (BHP) were investigated. In various testing systems, BHP showed a strong capability to enhance the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Moreover, BHP led to a significant decrease of malondialdehyde (MDA) level in animal serums. All the results indicated that BHP (with a major sequence of Cys-Glu-Arg-Pro-Thr-Cys-Cys-Glu-His-Ser) had a remarkable antioxidant activity in vivo . Meanwhile, no mortalities or evidence of adverse effects was observed in Sprague-Dawley rats following acute oral gavage with BHP at a dose of 10 g/kg body weight during the acute toxicity test. Furthermore, the negative results obtained in Ames test, bone marrow micronucleus test and sperm malformation test demonstrated that BHP had no obvious genetic toxicity to cause mutagenicity of microorganism gene, chromosome and genital cells. All the results suggested that BHP possessed the remarkable antioxidant activity in vivo and biological safety, and therefore had the potential value to be safely utilized as a natural antioxidant agent applied in pharmaceutical, cosmetic and medicinal industries.

This study explored the possible application of collagen hydrolysate (CH) in the fermentation process using Bacillus pumilus as probe bacterial strain. When CH acted as an only source of carbon and nitrogen in the culture medium, B. pumilus was observed to show normal characterizations during its growing process. Meanwhile, the utilization degree of CH by B. pumilus could be enhanced when wheat bran was added (used as carbon source) in the fermentation process. It was found that the highest alkaline protease activity was 325 U/mL when only CH was used, while it was increased to 620 U/mL with the addition of wheat bran. Besides, with different combination of soybean meal and CH, it was found that the ability using CH to produce alkaline protease is comparable to that of soybean meal in the presence of wheat bran. Moreover, the growth behaviors of the strain were not affected by inoculation concentrations, but the time of producing alkaline protease was greatly saved as reducing loading volume. Present investigation suggested that CH can be used as carbon and nitrogen sources in the fermentation process.

Developing efficient adsorbents with radiation stability for uranium removal from nuclear wastewater is greatly important for resource sustainability and environmental safety in manufacturing nuclear fuel. A novel adsorbent of hydrous titanium oxide-immobilized collagen fibers (HTO/CFs) with good radiation stability for UO22+ removal was developed. Results showed that the adsorption capacity of HTO/CFs for UO22+ was 1.379 mmol g−1 at 303 K and pH 5.0 when the initial concentration of UO22+ was 2.5 mmol L−1. Moreover, HTO/CFs showed high selectivity for U(VI) in bilateral mixed solution including UO22+ with another coexisting ion, such as Cl−, NO3−, Zn2+, and Mg2+. The adsorption behavior of UO22+ from radioactive wastewater on HTO/CF column was also investigated, and the breakthrough point was approximately 250 BV (bed volume). Notably, the HTO/CFs column can be rapidly regenerated by using only 4.0 BV of 0.1 mol L−1 HNO3 solution. The regenerated HTO/CFs column exhibited slight change in the breakthrough curve, suggesting its excellent reapplication ability. Furthermore, after irradiation under 60Co γ-ray at total doses of 10–350 kGy, HTO/CFs still preserved fibrous morphology and adsorption capacity, indicating significant radiation stability. These results demonstrate that HTO/CFs are industrial scalable adsorbents for the adsorptive recovery of uranium.

Ammonia and total nitrogen are concerned wastewater pollutants generated in beamhouse processing of leather production. Nitrogen pollution in tannery wastewater is mainly originated from unhairing/liming, deliming and bating processes due to the removal of non-collagenous proteins and the use of ammonium salts. In this study, protease assisted hair saving unhairing/liming, non-ammonia deliming and non-ammonia bating were integrated into a cleaner process to minimize nitrogen impact from the origin. It was found that the performances of the integrated cleaner beamhouse process were similar or better than conventional process. Leather made by the cleaner process exhibited comparable physical and morphological properties to conventional one. Ammonia nitrogen and total nitrogen in the wastewater from the cleaner process were reduced by 97% and 48%, respectively. Meanwhile, reductions of chemical oxygen demand, total solids and sulfide were also achieved.

The effect of ultrasound on the activity of α-amylase, papain and pepsin was investigated and the mechanism of the effect was explored by determining their conformational changes. With the irradiation of power ultrasound, the activity of α-amylase and papain was inhibited, while the activity of pepsin was activated. According to the analysis of circular dichroism, Fourier transform infrared and fluorescence spectroscopy, the πo → π(∗) amide transitions and secondary structural components, especially β-sheet, of these three enzymes were significantly influenced by ultrasound. The tryptophan fluorescence intensity of the three enzymes was also observed to be affected by sonication. Furthermore, it was found that the pepsin molecule might gradually be resistant to prolonged ultrasonic treatment and recover from the ultrasound-induced damage to its original structure. The results suggested that the activity of α-amylase, papain and pepsin could be modified by ultrasonic treatment mainly due to the variation of their secondary and tertiary structures.

The volatile constitutions of 36 raw liquors from three distilling stages (head, heart and tail) of two typical Luzhou-flavor liquors (Fenggu-FG and Jiannanchun-JNC) were identified and semi quantified by gas chromatography-mass spectrometry (GC-MS). A total of 63 compounds were identified in all liquors. These two typical liquors had similar volatile constitutions, in which, 3-methylbutanol, hexanoic acid, ethyl hexanoate, ethyl butanoate, ethyl lactate, ethyl pentanoate, 1,1-dimethoxythane and 1,1-diethoxy-3-methylbutane were considered to be main compounds due to their high concentrations. Multivariate analyses including principal component analysis (PCA) and partial least square-discrimination analysis (PLS-DA) were conducted to reveal the detailed distinctions of liquors with different origins and reveal the volatile markers of several kinds of liquors. PCA explanation plane primary revealed the main differentiation between FG and JNC based on their loading plot values on axis PC1. Results of PLS-DA showed the detailed distinctions of liquors, suggesting that 2-methylpropanoic acid, butanoic acid, pentanoic acid, nonanoic acid, 2,3-butanediol, 1-hexanol, and ethyl nonanoate strongly correlated with FG liquors, while n-butylformate, isopentyl butanoate, isoamyl caproate, and p-cresol contributed to the specificity of JNC liquors. Furthermore, differences amongst the heart distilling stage liquors from different enterprises were also visualized in the two-dimensional PLS-DA discrimination plane. To our knowledge, this is the first article using the GC-MS paired with multivariate analysis to discriminate different kinds of Luzhou-flavor raw liquors.

The pit mud (PM), a specific fermented soil, is an essential material for the fermentation of strong aromatic liquor. The microbial diversities of PM from different ages of strong aromatic liquor fermentation pits (20-, 50-, 100-, 200- and 300-year old) were investigated using combined phospholipid fatty acids (PLFAs) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. The total PLFA content of 20-year-PM (477.32 nmol/g) was significantly higher than that of other PMs (P

The separation of proteins is a key step in biomedical and pharmaceutical industries. In the present investigation, the collagen fiber adsorbent (CFA) was exploited as column packing material to separate proteins. Bovine serum albumin (BSA), bovine hemoglobin (Hb) and lysozyme (LYS) that have different isoelectric points (pIs) were selected as model proteins to investigate the separation ability of CFA to proteins. In batch adsorption, the adsorption behaviors of these proteins on CFA under different pHs and ionic strengths indicated that the electrostatic interaction plays a predominant role in the adsorption of proteins on CFA. CFA exhibited high adsorption capacity to Hb and LYS. In column separation, the proteins were completely separated by adjusting pH and ionic strength of the eluent. The increase of flow rate could reduce the separation time with no influence on the recovery of protein in the experimental range. The protein recovery was higher than 90% even when the CFA column was re-used for 4 times in separation of BSA and LYS, and the retention time of BSA or LYS was almost constant during the repeated applications. In addition, as a practical application, LYS was successfully separated from chicken egg white powder by CFA column.

Au@Pd bimetallic nanoparticles (NPs) catalysts were synthesized by a seeding growth method using bayberry tannin grafted collagen fiber (BT-CF) as the matrix. In this method, Au3+ was first reductively adsorbed onto BT-CF to form Au NPs, and then they serve as the seeds for the over growth of Pd shell. The morphology of BT-CF-Au@Pd catalyst was observed by TEM and SEM, and the core–shell structure of the Au@Pd was confirmed by EDS and XRD. It was found that the as-prepared BT-CF-Au9@Pd3 catalyst showed excellent synergy effect in liquid-phase hydrogenation of cyclohexene, whose reaction time was three times faster than that catalyzed by BT-CF-Pd catalyst under the same conditions. Meanwhile, the BT-CF-Au9@Pd3 catalyst could be re-used four times without significant loss of activity. In the fourth run, the substrate conversion was still as high as 92.70%, much better than that by using commercial Pd/C catalyst (42.60%). Additionally, BT-CF-Au9@Pd3 catalyst exhibited high hydrogenation activity to various alkenes and nitro-compounds. For example, the TOF of allyl alcohol, styrene and nitrobenzene hydrogenations reached 10,980, 14,732 and 1379 mol mol−1 h−1, respectively.

Bayberry tannin (BT), a typical plant polyphenol, was grafted on collagen fiber (CF) in different mass ratios. Subsequently, the BT-grafted CF (BT-CF) was used as carrier and stabilizer to prepare BT-CF stabilized silver nanoparticles (BT-CF-AgNPs). Scanning Electron Microscopy image of BT-CF-AgNPs showed that the BT-CF-AgNPs was in ordered fibrous state. X-ray Diffraction patterns and Transmission Electron Microscopy images offered evidence that the Ag nanoparticles were well dispersed on BT-CF. Fourier Transform-Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) investigations revealed that the Ag NPs were stabilized by the phenolic hydroxyls and quinones of BT on CF through electron donation/acception interaction. Antibacterial experiments demonstrated that BT-CF-AgNPs exhibited high antibacterial activity. When cell suspensions of Escherichia coli and Staphylococcus aureus (10 4 –10 5 cfu/mL) were contacted with BT 0.19 -CF-AgNPs (mass ratio of BT to CF = 0.19, conc. of Ag = 8 μg/mL) at 310 K under constant shaking, the number of cells went down to zero within 2 h. In addition, the minimal inhibitory concentration of BT 0.19 -CF-AgNPs against Escherichia coli , Staphylococcus aureus , Penicillium glaucum and Saccharomyces cerevisiae was 2 μg/mL, 4 μg/mL, 6 μg/mL and 12 μg/mL Ag, respectively. During recycling use, the antibacterial activity of BT 0.19 -CF-AgNPs against Escherichia coli can last for 5 cycles. These facts suggest that BT-CF-AgNPs can be used as a new and effective antibacterial agent.

Collagen fiber (CF), an abundant natural material of biopolymer, was used as supporting matrix for immobilization of catalase. CF was firstly reacted with Zr(IV), then the catalase was immobilized on Zr(IV)-modified CF (Zr–CF) by adsorption. The structures and properties of Zr–CF and the Zr–CF immobilized catalase (Zr–CF-catalase) were characterized by means of DSC, SEM, FT-IR, etc. It was found that the denaturation temperature of CF was remarkably increased from 37 to 75.6 °C after reacting with Zr(IV). The amount of catalase immobilized on Zr–CF was 45.4 mg/g. The K m and V max values were 23.3 mM and 3.5 × 10 4 U/mg for free catalase and 30.2 mM and 1.3 × 10 4 U/mg for immobilized catalase, respectively. Compared with free catalase, the Zr–CF-catalase exhibited higher relative activity in a broad range of pH and temperature (pH 3.0–8.0, 15–75 °C). For example, the relative activity of immobilized catalase is still 70.3% at pH 3.0 and 25 °C and 62.2% at pH 7.0 and 75 °C, which is rather higher than 45.6% and 41.2% of the free ones at the same conditions. Furthermore, Zr–CF-catalase could be reused 70 times before complete deactivation and preserve 86.5% of its original activities after stored at room temperature for 12 days.

A series of Rh nanoparticles were prepared by using plant tannins as stabilizers. The as-prepared plant tannin-stabilized Rh nanoparticles were subsequently characterized by TEM, DES, FTIR and XPS. Due to the amphiphilic nature of plant tannins, the plant tannin-stabilized Rh nanoparticles were highly active in aqueous–organic biphasic hydrogenation of styrene. Furthermore, the as-prepared Rh catalyst can be reused 5 times without significant loss of catalytic activity, thus exhibiting a remarkable reusability.

Effective recovery of UO2+2 from wastewater is essential for nuclear fuel industry and related industries. In this study, a novel adsorbent was prepared by loading titanium (Ti4+) onto collagen fiber (TICF), and its physical and chemical properties as well as adsorption to UO2+2 in nuclear fuel industrial wastewater were investigated. It is found that TICF can effectively recover UO2+2 from the wastewater with excellent adsorption capacity. The adsorption capacity is 0.62 mmol·g−1 at 303 K and pH 5.0 when the initial concentration of UO2+2 is 1.50 mmol·L−1. The adsorption isotherms can be described by the Langmuir equation and the adsorption capacity increases with temperature. The effect of co-existed F− on the adsorption capacity for UO2+2 is significant, which can be eliminated by adding aluminum ions as complexing agent, while the other co-existed ions in the solutions, including HCO−3, Cl−, NO−3, Ca2+, Mg2+ and Cu2+, have little effect on the adsorption capacity for UO2+2. The saturated TICF after UO2+2 adsorption can be regenerated by using 0.2 mol·L−1 nitrate (HNO3) as desorption agent, and the TICF can be reused at least three times. Thus the TICF is a new and effective adsorbent for the recovery of UO2+2 from the wastewater.

A novel fibrous sulfated ZrO2 (SO42−/ZrO2) solid acid catalyst was prepared using collagen fiber as the template. The surface morphology of the as-prepared catalyst was observed by scanning electron microscopy (SEM), and the corresponding crystalline properties were determined by X-ray diffraction (XRD). To collect the structural properties of the SO42−/ZrO2 catalyst, N2 adsorption/desorption method was carried out. Temperature-programmed decomposition (TPD) of ammonia was conducted to determine the acid strength of the catalyst. It was found that the SO42−/ZrO2 catalyst had well-defined fibrous morphology and porous structure, which contained both medium strong acidic sites and strong acidic sites. Subsequently, the esterification of acetic acid with n-butanol was carried out to evaluate the catalytic activity and reusability of the SO42−/ZrO2 catalyst. The SO42−/ZrO2 catalyst exhibited high catalytic activity as compared with other solid acid catalysts. Furthermore, the catalyst can be reused 6 times without significant loss of catalytic activity, suggesting a satisfied reusability.

A novel supported Pd catalyst was synthesized by using plant tannin grafted collagen fiber as the supporting matrix. The as-prepared Pd catalyst was subsequently used for the catalytic transfer hydrogenolysis of α-methylbenzyl alcohol. Due to the fibrous morphology of collagen fiber and the well dispersed Pd nanoparticles anchored by tannins, the as-prepared Pd catalyst showed superior activity for the catalytic transfer hydrogenolysis of α-methylbenzyl alcohol when compared with the Pd catalyst supported on inorganic oxides. Moreover, the as-prepared Pd catalyst can be reused at least 6 times without significant loss of activity and selectivity, suggesting a satisfied reusability.

A new strategy was provided by the introduction of plant tannins in porous Al2O3 to solve the problems of thermal migration of Pd during catalyst preparation, which ensured the preparation of heterogeneous Pd catalysts with well dispersion and superior activity. Compared with the conventional Pd–Al2O3 catalyst, the as-prepared heterogeneous Pd catalyst exhibited considerably improved Pd dispersion, which was highly active for the catalytic hydrogenation of olefins.

The collagen-tannin resin (CTR), as a novel adsorbent, was prepared via a reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to Cu(II) were systematically investigated, including pH effect, adsorption equilibrium, adsorption kinetics, and column adsorption. The adsorption capacity of Cu(II) on CTR was pH-dependent, and it increased with the increase of solution pH. The adsorption isotherms were well described by Langmuir isotherm model with correlating constant (R2) higher than 0.99. The adsorption capacity determined at 303 K was high up to 0.26 mmol/g, which was close to the value (0.266 mmol/g) estimated from Langmuir equation. The adsorption capacity was increased with the increase of temperature, and thermodynamic calculations suggested that the adsorption of Cu(II) on CTR is an endothermic process. The adsorption kinetics were well fitted by the pseudo-second-order rate model. Further column studies suggested that CTR was effective for the removal of Cu(II) from solutions, and more than 99% of Cu(II) was desorbed from column using 0.1 mol/L HNO3 solution. The CTR column can be reused to adsorb Cu(II) without any loss of adsorption capacity.

Collagen-tannin resin (CTR), as a novel adsorbent, was prepared via reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to UO(2)(2+) were investigated in detail, including pH effect, adsorption kinetics, adsorption equilibrium and column adsorption kinetics. The adsorption of UO(2)(2+) on CTR was pH-dependent, and the optimal pH range was 5.0-6.0. CTR exhibited excellent adsorption capacity to UO(2)(2+). For instance, the adsorption capacity obtained at 303 K and pH 6.0 was as high as 0.91 mmol UO(2)(2+)/g when the initial concentration of UO(2)(2+) was 1.0 mmol/L. In kinetics studies, the adsorption equilibrium can be reached within 300 min, and the experimental data were well fitted by the pseudo-second-order rate model, and the equilibrium adsorption capacities calculated by the model were almost the same as those determined by experiments. The adsorption isotherms could be well described by the Freundlich equation with the correlation coefficients (R(2)) higher than 0.99, the adsorption behaviors of UO(2)(2+) on CTR column were investigated as well. Present study suggested that the CTR can be used for the adsorptive recovery of UO(2)(2+) from aqueous solutions.

The aim of this study is to use collagen fiber (CF) as a natural polymeric support to synthesize a novel palladium (Pd) nanoparticle catalyst. To achieve a stable immobilization of Pd on CF support, epigallocatechin-3-gallate (EGCG), a typical plant polyphenol, was grafted onto CF surface, acting both as dispersing and stabilizing agent for Pd nanoparticles. Scanning electron microscopy showed that this catalyst was in ordered fibrous state with high flexibility. The presence of EGCG grafted on CF and the interaction mechanism of Pd ions with support was investigated by X-ray photoelectron spectroscopy. X-ray diffraction and transmission electron microscopy offered evidence that the well-dispersed Pd nanoparticles were generated on the outer surface of CF. By using the hydrogenation of allyl alcohol as a model reaction, the synthesized catalyst presented remarkably improved activity, selectivity and reusability as compared with the Pd catalyst supported by CF without grafting of EGCG.

Bayberry tannin (BT), a natural plant polyphenol, was used as a stabilizer to prepare supported platinum catalysts. Bayberry tannin was first grafted onto aminated SiO 2 beads and subsequently coordinate with Pt(IV) species. Then a series of heterogeneous Pt–bayberry tannin–SiO 2 (Pt–BT–SiO 2 ) catalysts was obtained after reduction with NaBH 4 . The catalysts were characterized by UV–DR, XRD and TEM, and the coordination state of Pt(IV) with BT grafted on SiO 2 beads was investigated by XPS. It was found that the Pt–BT–SiO 2 catalysts were highly active and stable in aqueous hydrogenation of acrylic acid, α-methacrylic acid, allyl alcohol and 2-methyl-3-buten-2-ol. Moreover, the Pt–BT–SiO 2 catalysts could be conveniently recovered from the reaction systems simply by filtration, and be reused at least five times without loss of activity.

A heterogeneous catalyst for Fenton reaction was prepared by immobilizing Fe(III) onto collagen fiber and its catalytic activity for the photo-assisted decomposition of Malachite Green (MG) was investigated. The results indicated that this Fe(III)-immobilized collagen fiber (Fe-CF) can effectively catalyse the decoloration and decomposition/mineralization of MG in aqueous solution. Catalysed by Fe-CF, MG solution was completely decolorized in 30 min, while 55.0% of TOC was removed from the dye solution within 120 min in the presence of H 2 O 2 and UVA irradiation (365 nm, 10 W). Fe-CF was recycled for seven times with certain activity loss (32.6% in decoloration, 18.5% in TOC removal), and its catalytic activity can be easily recovered by re-immobilization of Fe(III). Therefore, Fe-CF could act as an efficient and cost-effective catalyst for the photo-assisted decomposition of MG, and shows potential applications in practice.

The homogeneous ruthenium complexes were immobilized onto tannin grafted micelle templated silica (MTS–BT) to prepare heterogeneous MTS–BT–Ru catalysts. The catalyst was found to be highly active in liquid phase hydrogenation of olefins. The heterogenized Ru complexes also exhibited excellent stability, reusability and catalytic efficiency. Furthermore, this methodology could extend to heterogenize other complexes to improve their reusability and stability.

A novel heterogeneous palladium (Pd) nanoparticle catalyst stabilized by collagen fibers (CF) was synthesized. Epigallocatechin-3-gallate (EGCG), a typical natural polyphenol, was grafted onto the CF surface to improve the stabilization and immobilization of Pd(0) nanoparticles. The main physical and chemical properties of the catalyst were characterized by means of Scanning Electron Microscopy, Fourier Transform-Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, X-ray Diffraction and Transmission Electron Microscopy. This catalyst is in an ordered fibrous state with high flexibility. The Pd(0) nanoparticles with diameters of 3–4 nm are homogeneously dispersed onto the outer surfaces of CF, and they are stabilized by the coordinative interactions between the surface Pd atoms of nanoparticle and the surrounding oxygen and nitrogen atoms of the EGCG-grafted CF. These stabilized Pd(0) nanoparticles were found to be active and selective catalysts for nitrobenzene and its derivatives, directly hydrogenating to the correspondingly reductive anilines under mild conditions. Both Pd particle size and activity of the catalyst showed a marked dependence on the grafting degree of EGCG on CF. These catalysts can be easily recovered, reused multiple times, and stored for two months in air while maintaining high catalytic efficiencies. All these facts suggest that the EGCG-grafted CF can be used as an effective stabilizer for the preparation of Pd(0) nanoparticle catalysts.

Hierarchical mesoporous ZrO 2 -carbon fiber was successfully synthesized by using collagen fiber as a structure-directing agent, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The ZrO 2 -carbon fiber obtained is approximately 1–4 μm in outer diameter and 0.5–1 mm in length, and the surface of the fiber exhibits ordered corn-cob-like mesoporous morphology.

The adsorption of Pt(IV) and Pd(II) on bayberry tannin immobilized collagen fiber (BTICF) membrane was investigated. The optimal pH for the adsorption of Pt(IV) and Pd(II) ions was found to be 3.0 and 4.0, respectively. The time for attaining adsorption equilibrium of Pt(IV) and Pd(II) was 60 and 240 min. The adsorption kinetic data of the two metal ions are well fitted by the pseudo-second-order model. The adsorption capacities of Pt(IV) and Pd(II) on 0.100 g BTICF membrane were 41.7 and 27.5 mg/g at 313 K. The adsorption isotherms of the membrane to both the ions are described by the Langmiur model. The adsorption extent remarkably increases with the increase of temperature and the ratio of membrane material to solution volume. The membrane saturated by Pt(IV) is easily regenerated by 0.1 M thiuorea, but the full regeneration is difficult after adsorption of Pd(II). The continuous adsorption experiments of 58.3 mg/L Pt(IV) and 48.8 mg/L Pd(II) solutions were undertaken by using three layers of membrane (total area 191 cm 2 ), and it was found that no Pt(IV) and Pd(II) ions were detected until 700 and 1000 ml effluents were collected, respectively. Furthermore, competitive adsorption studies revealed that the membrane exhibits ability of selective adsorption to Pt(IV) and Pd(II) in the mixture solutions of metal ions. © 2005 Elsevier B.V. All rights reserved.

A novel adsorption membrane was prepared by immobilizing condensed vegetable tannins onto collagen fiber membrane. The tannins immobilized onto the membrane keep their ability of chelating metal ions and can withstand the exposure to water and organic agents. The adsorption capacities of bayberry tannin and black wattle tannin immobilized membranes to U O 2 2 + were 56.8 mg U/g and 53.0 mg U/g, respectively, at 303 K when the initial concentration of U O 2 2 + was 263 mg U/L.The adsorption isotherm of tannins immobilized membrane to U O 2 2 + can be described by the Freundlich model. The adsorption kinetics of the membrane to U O 2 2 + can be well described by the pseudo-second-order rate model. The adsorption capacity calculated by the pseudo-second-order rate model was closed to that determined by actually measurement. The continuous adsorption–desorption studies indicated that this kind of adsorption membrane has excellent adsorption–desorption properties. For monolayer membrane, more than 90% U O 2 2 + was adsorbed when 500 mL U O 2 2 + solution (conc. 263 mg U/L) passed through it. When three layers of membrane were employed, no U O 2 2 + was detected until 1000 mL the effluent was collected. The membrane can be easily regenerated by a small quantity of 0.1 M HNO3 after adsorption, and therefore U O 2 2 + can be greatly concentrated. The repeated adsorption–desorption experiments confirmed that the tannins immobilized membrane could be used for at least 10 times without considerable decrease of adsorption capacity.