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We confirmed that reducing the use of a ruthenium catalyst can achieve a similar depolymerization efficiency only by extending the reaction time, and butanone extraction can achieve the separation of inorganic salts and organic components.

A clean and efficient conversion process is essential for the utilization of low-rank coals. Lignite, a typical representative of the low-rank coal family, has huge potential for the production of valuable chemicals via the oxidative depolymerization reaction. Ruthenium ion-catalyzed oxidation (RICO) is an effective route for lignite depolymerization under mild conditions, but the high cost of precious Ru limits the potential large-scale application of RICO. How to recycle and reuse Ru is critical to promote the application of RICO. In this work, a novel and efficient approach for reusing Ru through recycling the solvent mixture containing Ru was established for RICO. First, the influence of different reaction parameters on the depolymerization degree of lignite and benzene polycarboxylic acid (BPCA) yields was investigated. Second, the distribution of Ru in the organic phase (OP), aqueous phase (AP), and residual solid phase (RSP) was analyzed after the RICO reaction. Finally, based on the distribution of Ru in different phases, a novel route of recycling Ru by reusing the Ru-containing solvents was proposed. The results showed that the dosage of RuCl3 and NaIO4 had a significant influence on both the depolymerization degree of lignite and BPCA yields. The distribution of Ru had a close relationship with the depolymerization degree of lignite and the dosage of NaIO4. After the depolymerization reaction, the CCl4 phase containing Ru was reused directly as the solvent for the next run, which could fulfill the reuse of both CCl4 and Ru. The results proved that the Ru-containing CCl4 phase could maintain catalytic performance for 5 runs. This work provides an efficient route to reuse Ru for the RICO depolymerization of lignite into valuable organic acids. As far as we know, this is the first report concerning the recycling and reuse of Ru during the RICO of lignite. This work is important for the application of RICO in lignite depolymerization.

Calcium has been proved to be efficient for the catalytic steam gasification of lignite. In this study, we studied the steam gasification of lignite with Ca(OH)2 added by wet impregnation for to produce hydrogen. The effect of calcium on the microstructural evolution and char gasification behavior in the presence of steam were studied. The distribution of the gaseous products was examined by using fixed-bed micro reactor equipment for steam gasification. Partially gasified chars obtained at different temperatures (400, 500, 600, and 700 °C) in the gasification process were characterized by scanning electron microscopy coupled with energy dispersive spectroscopy, 13C nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and Raman spectroscopy. The results suggested that a “Ca-carboxylate-like structure” was formed due to the addition of calcium to lignite. This Ca-carboxylate-like structure increased the thermal stability of the original carboxylic structure in lignite. As a result, the calcium-added coal retained more oxygen-containing structures, formed more defects, and possessed significantly lower aromatic structures due to the formed Ca-complexes during steam gasification. Therefore, it can be inferred that the Ca-complexes in the lignite char increased the gasification reactivity of char.

Due to the low utilization efficiency of lignite as a primary energy source, the valuable and clean use of lignite becomes important. Oxidative depolymerization of lignite into valuable organic acids (VOAs) has been identified to be feasible, but the difficulty in separating VOAs from the complex lignite depolymerized mixture (LDM) limits the potential application of this route. In this study, based on the coordination interactions between metal ions and carboxylate groups in VOAs, the metal ion-induced separation of VOAs from the LDM was proposed. The results proved that most of the studied metal ions (Mn+) could selectively form M–VOA precipitates with the VOAs in LDM and transferred the VOAs from the water phase into the solid precipitates. Then, the intermediate M–VOAs could be dissolved in diluted NaOH solution to release the VOAs, with Mn+ being transformed into M(OH)n. The separation yield and selectivity could be tuned facilely by various metal ions at different dosages, pH, and temperatures. The process could be fulfilled under near-room temperature in water without the use of organic solvents. Due to its efficiency, tunable selectivity, and green nature, the proposed separation strategy may find potential applications in the valuable and clean use of lignite sources.

Use of lignite under mild conditions without destroying the natural functional groups and structures is a potential approach for the value-added utilization of lignite. Considering the abundant acidic functional groups in lignite, in this work, a novel and facile route using lignite as robust organic ligands to construct Zr-based catalysts was proposed, and the designed catalysts were applied in the conversion of biomass-derived carbonyl molecules into valuable chemicals. The universality of the proposed route for different rank coals and substrates with various structures were analyzed. Both the preparation conditions of the catalysts and the reaction parameters were systematically investigated. The obtained catalysts were characterized by SEM-EDS, XRD, FTIR, Raman, and TG, etc. The results demonstrated that the designed catalysts were highly efficient for the selective conversion of furfural into furfuryl alcohol. Under the optimized conditions, the conversion, yield, and selectivity were up to 93.4%, 81.0%, and 86.7%, respectively. Both the reaction conditions and the performances of the catalyst were competitive compared with analogous catalysts. It was proved that the catalyst was heterogeneous and the reusability could be improved through demineralization of lignite via acid washing before use, and the catalyst prepared by demineralized lignite had no obvious changes in both performances and structures after 5 reuses. The proposed route was also identified to be applicable for other low rank coals besides lignite, such as long flame coal and coking coal. The catalyst prepared using lignite was robustly effective for the conversion of various carbonyl compounds with different structures, indicating the broad universality for different substrates. Detailed characterization showed that the performances of the catalyst were jointly influenced by both Zr contents and surface areas of the catalyst. This novel route of constructing Zr-based catalysts using low rank coal as raw materials is highly potential for application in the utilization of low rank coals and biomass resources, with the advantages of high efficiency of the catalysts, low cost of raw materials, and simple preparing process.

CuO–Ni/Al composites were synthesized by electroless deposition and thermal oxidation and characterized by inductively coupled plasma optical emission spectrometry, X-ray powder diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their performances as the heterogeneous catalysts for the solvent-free allylic oxidation of cyclohexene by oxygen were determined. It was found that the CuO contents and the amount of adsorbed oxygen species on the composites could significantly affect their catalytic performances in cyclohexene oxidation. The highest catalytic activity was achieved over CuO–Ni/Al-3 containing 18.5 wt% CuO with the highest amount of adsorbed oxygen species, which resulted in the maximum cyclohexene conversion of 39.1% and the total selectivity of 85.5% to 2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2-cyclohexene-1-hydroperoxide and cyclohexene oxide. In addition, the catalyst was successfully recycled with no significant catalytic activity loss after three cycles.

Hydrogenation of biomass-derived ethyl levulinate (EL) to gamma-valerolactone (GVL) is an important step in the conversion of sustainable biomass resources into value-added chemicals. Exploration of highly efficient and easily obtainable catalysts is crucial for the large-scale application. In this work, a series of cobalt catalysts were prepared by one-step reduction route in different solvents and applied into the conversion of biomass-derived EL to GVL. Common solvents, including water, methanol, ethanol, glycol and glycerin were attempted as the solvent. Both the solvent effect on the catalyst synthesis and the hydrogenation reaction parameters during the conversion of EL into GVL were systematically investigated. The catalysts were characterized by SEM-EDS, TEM, powder XRD, N2 adsorption-desorption, and XPS. The results demonstrated that the solvents had significant influences on the morphology and structure of the as-prepared catalysts, which changed from dendrite (in water) to spheres (in glycerin). All the catalysts prepared in different solvents were effective for the conversion of EL. Under the optimized conditions, a high GVL yield of 91.4% was achieved when using cobalt catalyst prepared in ethanol at relatively mild reaction conditions. Furthermore, the catalyst could be reused at least 6 times without significant loss of the catalytic activity. As far as we know, this is the first work on the application of cobalt catalysts, synthesized by one-step solution phase reduction method, in the conversion of EL into GVL in biomass utilization.

It is important to inhibit the spontaneous combustion of lignite for its safe transportation and efficient utilization. Shengli lignite was treated with a NaOH solution and the as-prepared coal samples were extensively characterized by SEM-EDS, XRD, FT-IR, XPS, and Raman spectra techniques. The combustion properties of NaOH treated lignite were determined by TGA. The results show that NaOH treatment played a significant inhibitory effect on the combustion performance of Shengli lignite. The NaOH treated lignite showed two weight loss temperature regions. The temperature corresponding to the maximum combustion rate of Shengli lignite after the NaOH pretreatment was about 350–400 °C, higher than that of untreated sample, indicating that NaOH treatment significantly decreased the combustion reactivity of Shengli lignite. FT-IR and XPS analyses identified the analogous sodium polycarboxylic acid, originating from the crosslinking combination of carboxyl functional groups with NaOH. It is deduced that the suppressing effect of NaOH treatment on the combustion performance of lignite maybe attributed to the higher stability of analogous sodium polycarboxylic acid.

With the fast depletion of fossil resources, exploring the value-added utilization approaches of low rank coals and promoting the conversion of sustainable biomass resources into useful chemicals are critical topics facing human society. In this work, we attempted low rank lignite as raw materials to construct novel Zr-based catalysts for biomass conversion using the abundant oxygen-containing groups and specific network structures of lignite. Two components of lignite, i.e. humic acids (HA) and the solid residues (SR) after HA extraction, were used to prepare the catalysts. The prepared catalysts were applied into the conversion of biomass-derived ethyl levulinate (EL) to gamma-valerolactone (GVL), an important reaction for the conversion of biomass resources. Both the preparation conditions of the catalysts and the parameters during catalytic reaction process were systematically investigated. The structures of the catalysts were characterized by SEM, TEM, FTIR, powder XRD, and TG analysis. The results demonstrated that the route using lignite as raw materials to construct Zr-based catalysts was feasible, and the designed catalysts were highly efficient for the conversion of EL into GVL. The conversion of EL, GVL yield and selectivity could reach up to >90% under suitable conditions. The catalysts could be used at least 11 recycles without notable changes in both performances and structures, indicating an excellent stability. This work may provide potential ways for both value-added utilization of low rank coals and construction of efficient catalysts for biomass conversion.

The catalytic effect of calcium on the steam gasification of Shengli chars was studied in this work. The calcium-added chars were prepared by pyrolysis under argon atmosphere from calcium oxide added demineralized Shengli lignite. The chars were characterized in detail by SEM-EDX, XRD, Raman, FTIR and XPS and were tested on a fixed-bed reactor to evaluate its performances steam gasification. Calcium was found to have significantly promotional effect on the steam gasification of char samples with reduces of activation energy. It was observed the presences of 5 wt% or above in the char significantly enhanced H2 productions, which resulted in high H2/CO ratio of syngas. The SEM-EDS and XRD results suggested calcium was highly dispersed within the char particles, CaO and CaS presented in the char samples, but the hydrochloric acid treatment of the char caused significant loss of these calcium compounds. The steam gasification rate of the acid-treated samples was still much higher than that of the no-calcium-added char, which elucidates that superior steam gasification performance of the Ca-added chars was not the simple CaO species in the char, instead, a special calcium lignite intermediate complex “R1-O-Ca-O-R2” (R representing aromatic or aliphatic constituents), formed within char during the pyrolysis. Thus the crosslink-like intermediate complexes “R1-O-Ca-O-R2” structure between calcium and chars was postulated to be the decisive factor to promote the steam gasification of Shengli chars with more production of high hydrogen syngas.

As the fast depletion of coal resources, exploring the value-added utilization approaches of low rank coals or their components and, in parallel, promoting the conversion of sustainable resources (such as biomass) into useful chemicals are critical issues facing human society. In this work, we used humic acids (HAs), an abundant material in nature (mainly derived from low rank coals), and the transition metal zirconium (Zr) to prepare a novel Zr-containing hydrogen transfer catalyst. The prepared catalyst was applied into the conversion of biomass-derived ethyl levulinate (EL) into gamma-valerolactone (GVL) via hydrogen transfer reaction. Both the preparation conditions of the catalysts and the reaction parameters during the conversion of EL into GVL were systematically investigated. The catalyst was characterized by SEM, TEM, FTIR, powder XRD, and TG analysis. The results demonstrated that the as-prepared catalyst was highly efficient for the conversion of EL into GVL. Under optimized conditions, EL could be completely converted and the GVL yield could reach up to 88.3%. The catalyst could be used at least 11 times without notable changes in both activity and structures, indicating an excellent stability. As far as we know, this is the first work using HAs to prepare Zr-containing catalyst and its application to the conversion of EL into GVL in biomass utilization.

The steam gasification of Shengli (SL) lignite and the demineralized lignite/chars were tested on a laboratory fixed-bed micro reactor system. The evolution rates of syngas, carbon conversions to gas, yields of gaseous products, and H2/CO molar ratios of SL lignite/chars were systematically investigated. Meanwhile, the gasification performance of SL lignite/chars was compared with the corresponding demineralized samples. The results showed that the inherent minerals in SL lignite/chars not only effectively promoted the steam gasification reaction but also considerably improved the gasification selectivity towards the production of H2 and CO2. Further characterizations by the scanning electron microscope (SEM-EDS) and X-ray fluorescence (XRF) demonstrated that it became more difficult for the minerals in SL lignite being eluted by hydrochloric acid solution with the temperature increasing of pyrolysis process. The results confirmed that the inherent minerals and lignite formed metals-lignite intermediate complex during pyrolysis process. The formed metals-lignite intermediate complex works as the active sites which effectively promote the steam gasification performance of SL lignite/chars, especially in favor of the direct generation of high hydrogen syngas.

Research on the structural and combustion properties of coal is of great importance for its conversion and applications in view of fundamental studies. In this work, we conducted the first detailed study on the structural properties and combustion kinetics of Chinese Shenhua raw coal (RC) and its pyrolytic char (PC). The combustion kinetics was simulated by using the random pore model (RPM). The results showed that RC and PC were composed of both a plant-cell-like structure and a discrete particulate structure. In addition, PC had a larger specific surface area, finer particles, higher aromaticity, and higher degree of aromatic ring condensation than those of RC. Combustion of PC showed higher ignition temperature, lower burnout temperature, and a higher combustion index compared to RC. A high correlation coefficient R2 (0.999) and a low average error θ (0.008) were obtained using the RPM. The combustion apparent activation energy E and the structural parameter ψ of RC were 40.30 kJ mol−1 and 0.53, respectively. For PC, the values of E and ψ were estimated to be 60.01 kJ mol−1 and 0, respectively. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

Spontaneous combustion has become a critical limiting factor for the safe and efficient utilization of low rank coals. In this work, the alkali-oxygen oxidation (AOO) of Chinese Shengli lignite was conducted to inhibit the spontaneous combustion tendency, and the influences of AOO on the structures and combustion properties were investigated. The structures of AOO treated lignite under different conditions were characterized by XRD, Raman, XPS and FTIR. The combustion characteristics of the samples were investigated by thermogravimetric analysis and fixed bed combustion. The results revealed that the temperature of AOO treatment had significant influence on the crystallite structures and combustion characteristics of Shengli lignite. After the AOO pretreatment, the benzene ring skeleton structures in lignite had no obvious changes, but the amounts of aliphatic side chains on the aromatic nucleus decreased. Compared with raw lignite, the degree of order and ignition temperature increased after AOO treatment, especially when the AOO temperature was 150–200 °C. The ignition temperatures moved from 310 °C for raw lignite to 740–760 °C for the samples treated by AOO at 150–200 °C. On further increasing the AOO temperatures to 250–300 °C, the ignition temperature of the samples decreased to 410–440 °C. In conclusion, AOO pretreatment under suitable conditions is an efficient way to inhibit the spontaneous combustion tendency of low rank lignite, and it is believed that the results in this work are meaningful for the safe transportation and efficient utilization process of lignite in industry.

With the increasing demands for energy and carbon resources, exploration of novel utilization approaches of fossil resources and promotion of the conversion of sustainable resources become critical issues facing human society. In this study, we used humic acids (HAs), which are important derivatives from the low-rank coal, and the transition metal zirconium (Zr) to construct novel Zr-containing catalysts (Zr-HAs) for Meerwein–Ponndorf–Verley (MPV) reactions of biomass-derived platforms. Both commercial HAs and HAs extracted directly from lignite without any purification were used as raw materials to prepare the catalysts. The results showed that Zr-HAs catalysts were highly efficient for the conversion of furfural, with a high furfuryl alcohol yield of up to 97%, and also effective for the conversion of other carbonyl compounds with different structures under mild conditions. This novel strategy to construct catalysts using HAs as raw materials may be beneficial for both value-added utilization of low-rank coal and the conversion of biomass resources.

Investigation of the effects of demineralization of inherent minerals in Shengli lignite (SL) on its structure and combustion property in the field of coal conversion is an extremely important and interesting topic. In this study, inherent minerals in SL were demineralized by hydrochloric acid (HCl) treatment. Further, the metals cations Na + , Al 3+ , K + , Ca 2+ , Mn 2+ and Fe 3+ , corresponding to the inherent metal ions in lignite were added into the demineralized samples by the impregnation method in order to compare their effects. The surface morphology and structure parameters of the raw and demineralized lignite samples were characterized by SEM, nitrogen adsorption–desorption, FTIR, XPS, XRD and Raman spectroscopy. The combustion properties of lignite samples were investigated by thermogravimetric analysis. Demineralization led to an improvement in the amount of side chains in SL and destroyed the pore structure and aromaticity; however, it did not have obvious effects on the surface morphology of SL and the main forms of carbon and oxygen. Moreover, demineralization increased the ignition temperature and apparent activation energy, and decreased the combustion stability index of SL. Added aluminum ions resulted in a decrease in the combustion stability and reactivity of the HCl treated sample; however, the added metals cations such as Na + , K + , Ca 2+ , Mn 2+ and Fe 3+ , exhibited opposite effects.

Conversion of biomass into 2,5-dimethyltetrahydrofuran (DMTHF), an excellent fuel additive, solvent, and industrial intermediate, is an important reaction in green chemistry. In this work, different combinations of supported metal catalysts and solid acids were investigated for the synthesis of DMTHF from biomass derived diketone (2,5-hexanedione, 2,5-HD). The results showed that commercial Pt/C and solid acid Amberlite®IR-120H had an excellent cooperative effect on the reaction. 2,5-HD could be converted into DMTHF with a yield up to 99% under milder conditions. Further experiments indicated that 2,5-hexanediol (2,5-HDO) is a key intermediate in the reaction. The catalyst system could be facilely recovered due to the heterogeneity and reused several times without notable change in the performance.

This work reports the utilization of hydrogen in water for the hydrogenation of organic compounds and the oxygen for the oxidation of glucose simultaneously by photocatalysis., Direct utilization of the abundant hydrogen and oxygen in water for organic reactions is very attractive and challenging in chemistry. Herein, we report the first work on the utilization of the hydrogen in water for the hydrogenation of various organic compounds to form valuable chemicals and the oxygen for the oxidation of glucose, simultaneously by photocatalysis. It was discovered that various unsaturated compounds could be efficiently hydrogenated with high conversion and selectivity by the hydrogen from water splitting and glucose reforming over Pd/TiO2 under UV irradiation (350 nm). At the same time, glucose was oxidated by the hydroxyl radicals from water splitting and the holes caused by UV irradiation to form biomass-derived chemicals, such as arabinose, erythrose, formic acid, and hydroxyacetic acid. Thus, the hydrogen and oxygen were used ideally. This work presents a new and sustainable strategy for hydrogenation and biomass conversion by using the hydrogen and oxygen in water.

Transformation of anisole (methoxybenzene), a typical component of bio-oil, into phenol and methylated phenols was studied over HY zeolites with framework Si/Al ratios of 5, 15, 25, and 35. It was demonstrated that the amounts of BrOnsted acid and Lewis acid sites, the ratio of Lewis acid and BrOnsted acid sites, and the textural properties of the zeolites were all crucial parameters that influenced the catalytic performance. The BrOnsted acid and Lewis acid sites of the zeolites catalyzed the reaction cooperatively and efficiently promoted the transmethylation. The hierarchical channel system with fully open micropore-mesopore connectivity was favorable to reduce the amount of coke generated.

Ionic liquid 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BnMIm][NTf2]) can promote the generation of the ˙OOH free radical and thereby efficiently transformed the β-O-4 lignin model compound 2-phenoxyacetophenone into benzoic acid and phenol using O2 as the oxidant. Furthermore, the IL-based metal-free catalytic system can also depolymerize other lignin model compounds and organosolv lignin effectively.

Catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) to γ-valerolactone (GVL) is a very attractive reaction in the field of biomass transformation. In this work, a new porous Zr-containing catalyst with a phenate group in its structure was prepared by the coprecipitation of 4-hydroxybenzoic acid dipotassium salt and ZrOCl2 (Zr-HBA) in water and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption, and Fourier transform infrared spectroscopy. The Zr-HBA was used as the catalyst for CTH of EL to GVL in the presence of isopropanol, and the effects of temperature, time, and the amount of the catalyst on the reaction were studied. It was found that Zr-HBA was very active for the reaction and a GVL yield of 94.4% could be achieved. Meanwhile, the Zr-HBA could be reused at least five times without a notable decrease in activity and selectivity. The main reason for the high catalytic activity of the Zr-HBA was that the existence of a phenate in the structure of Zr-HBA increased the basicity of the catalyst, which is favourable for the CTH of EL.

Both effective utilization of glycerol and reduction of nitrobenzene to aniline are of great importance. It is very interesting to integrate these processes. This work reports the integration of the efficient conversion of nitrobenzene to aniline and transformation of glycerol to valuable chemicals driven by UV-light using Pd/TiO2 as the catalyst and water as the solvent at ambient temperature. In this integrated reaction process, glycerol acted as the hydrogen source for the reduction of nitrobenzene to aniline and the glycerol was converted into value-added chemicals simultaneously. At the optimized conditions, nitrobenzene could be converted completely with aniline selectivity of 95% with a nitrobenzene to glycerol mole ratio of 1 : 5. At the same time, glycerol was oxidized to form fine chemicals, including 1,3-dihydroxyacetone, glyceraldehyde, formic acid, and hydroxyacetic acid. This work opens up a new and effective way for transformation of glycerol to fine chemicals and production of aniline from nitrobenzene.

Efficient conversion of glucose to 5-hydroxymethylfurfural (HMF), an important platform molecular for fuels and chemicals, is a promising topic in green chemistry. In this work, several new DBU-based (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene) ionic liquids (ILs) with benzene sulfonate (BS) anion were synthesized and used as the solvents for the dehydration of glucose to HMF. It was found that all the ILs were excellent solvents for the dehydration of glucose to form HMF using CrCl3 as the catalyst. The effects of various factors, such as kind of catalysts, catalyst amount, reaction time and reaction temperature, on the yields of HMF were studied systematically in the Et-DBUBS/CrCl3 catalytic system. The yield of HMF from glucose could reach 83.4% under the optimized reaction conditions, and the reasons for the high yield were investigated on the basis of control experiments. The Et-DBUBS/CrCl3 system could be reused at least five times without considerable reduction in the efficiency. Further study indicated that the catalytic system was also very efficient for transformation of fructose, inulin, and cellobiose to HMF.

A novel separation technology at room temperature for traditional Chinese medicines was proposed in this work by adding magnetic molecularly imprinted polymers (M-MIPs) into extraction solution and sample matrix. The M-MIPs show a more adsorption capacities and higher selectivity for the template than magnetic non-molecularly imprinted polymers (M-NMIPs) without the specific binding sites. Addition of the M-MIPs to the extraction solution provides one-step extraction and cleanup, the improvement of extraction rate and extraction yields of three tanshinones (from 0.40, 0.23 and 0.12 mg g(-1) in 240 min by solvent extraction to 0.52, 0.27 and 0.19 mg g(-1) in 5 min by 200 mg sorbent), and reusability of extraction solvent. The extraction yields of three tanshinones by this technology at room temperature in 5 min were higher than those by ultrasonic extraction in 30 min, by heat reflux extraction in 45 min and by solvent extraction at room temperature in 4 h. The integrated technology has the advantages of one-step extraction and cleanup, high extraction efficiency, low solvent consumption and room temperature. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.

In this study, gas-assisted superparamagnetic extraction (GASE), a novel technology that combined superparamagnetic extraction technology with flotation technology, was proposed for potential large-scale separation of proteins. GASE includes adsorption for trapping proteins, and flotation and high gradient magnetic separator (HGMS) for recovering proteins-loaded magnetic particles from the dilute biosuspension. Citrate-modified superparamagnetic nanoparticles (CMNs) and bovine serum albumin (BSA) were used as a model. The feasibility of flotation for these particles enrichment was demonstrated. The results indicated that the BSA-loaded CMNs could be well concentrated in either foaming flotation or nonfoaming flotation by simple adjustment of the initial solution pH, without extra detergents and operations. The flotation conditions were consistent with the adsorption ones, and no proteins were desorbed from CMNs in the GASE process. Under the optimal conditions, the enrichment ratio and recovery percentage reached 31 and 99% in 1.5 min, respectively.

With the aim of improving the stability of penicillin G acylase (PGA), functional ionic liquids (ILs) were used to modify the surface chemistry of the supports on which they were physically adsorbed. Four kinds of ILs—specifically, 1-methyl-3-(triethoxysilylpropyl)-imidazolium salts, with Cl–, BF4–, PF6–, and Tf2N– as the anions (IL-Cl–, BF4–, PF6–, and Tf2N–, respectively)—were used to tune the hydrophilic or hydrophobic properties of the ILs. The synthesized ILs were first immobilized on magnetic silica nanoparticles (Fe3O4/SiO2), and the composite material (Fe3O4/SiO2–IL) was then applied to immobilize PGA via physical adsorption. The amount of protein loading, the specific activity, the immobilization yield, and the stability of immobilized PGA were investigated to evaluate the effects of the ILs on the PGA immobilization. The results showed that PGA immobilized on Fe3O4/SiO2–ILs was more stable than that immobilized on Fe3O4/SiO2 with no IL modification. Among the four kinds of ILs tested, the hydrop...

The utilization of compounds from natural sources to prepare functional materials is of great importance. Herein, we describe for the first time the preparation of organic–inorganic hybrid catalysts by using natural phytic acid as building block. Zirconium phosphonate (Zr-PhyA) was synthesized by reaction of phytic acid and ZrCl4 and was obtained as a mesoporous material with pore sizes centered around 8.5 nm. Zr-PhyA was used to catalyze the mild and selective Meerwein–Ponndorf–Verley (MPV) reduction of various carbonyl compounds, e.g., of levulinic acid and its esters into γ-valerolactone. Further studies indicated that both Zr and phosphate groups contribute significantly to the excellent performance of Zr-PhyA.