Performance and mechanism of a bioelectrochemical system for reduction of heavy metal cadmium ions.

This study explores the removal of Cd(ii) from wastewater using a microbial electrolysis cell (MEC) to investigate the electrochemical performance and removal kinetics of an anodic polarity reversal biocathode and the mechanism of action of electrochemically active bacteria. Comparative electrochemical methods showed that using an anodic polarity reversal biocathode resulted in greater than 90% removal of different concentrations of Cd(ii) within three days, which may be related to the catalytic effect of anodic electrochemically active bacteria. However, due to the ability of bacteria to regulate, up to nearly 2 mg L-1 of Cd(ii) ions will remain in solution. As shown by the linear fitting relationship between scanning speed and peak current, the removal process was dominated by adsorption control for 20-80 mg L-1 Cd(ii) and diffusion control for 100 mg L-1 Cd(ii). The analysis of raw sludge and sludge containing Cd(ii) showed that Arcobacter and Pseudomonas were the primary cadmium-tolerant bacteria, and that the ability to remove Cd(ii) was the result of a synergistic collaboration between autotrophic and heterotrophic Gram-negative bacteria.

Preparation of the recycled and regenerated mesocarbon microbeads-based solid acid and its catalytic behaviors for hydrolysis of cellulose.

Mesocarbon microbeads (MCMB) from coal tar pitch have excellent mechanical strength, high density, and good thermal stability. Moreover, a great deal of aromatic constituents occur on its surface, favoring the substitution reaction of sulfonic group. Results showed that the total acid and -SO3H amount was 4.36 mmol/g and 2.18 mmol/g, respectively. Moreover, the yield of total reducing sugar (TRS) and conversion ratio (Cr) for pretreated cellulose (DP = 101.5) can reach 66.7% and 68.8% at 140 °C for 240 min in distilled water, respectively. After four recycles, the TRS and Cr decreased by 12.6% and 10.2%, respectively. Through the secondary and third regeneration for the catalyst, acid density still reached 88.1% and 87.2% of the initial R1-MCMB-SO3H, demonstrating excellent regeneration ability and recyclability of the solid acid. Therefore, MCMB-based solid acid exhibits an attractive potential in the conversion of cellulose into platform chemical compounds.

Upgrading pyrolytic residue from waste tires to commercial carbon black.

The managing and recycling of waste tires has become a worldwide environmental challenge. Among the different disposal methods for waste tires, pyrolysis is regarded as a promising route. How to effectively enhance the added value of pyrolytic residue (PR) from waste tires is a matter of great concern. In this study, the PRs were treated with hydrochloric and hydrofluoric acids in turn under ultrasonic waves. The removal efficiency for the ash and sulfur was investigated. The pyrolytic carbon black (PCB) obtained after treating PR with acids was analyzed by X-ray fluorescence spectrophotometry, Fourier transform infrared spectrometry, X-ray diffractometry, laser Raman spectrometry, scanning electron microscopy, thermogravimetric (TG) analysis, and physisorption apparatus. The properties of PCB were compared with those of commercial carbon black (CCB) N326 and N339. Results showed PRs from waste tires were mainly composed of carbon, sulfur, and ash. The carbon in PCB was mainly from the CCB added during tire manufacture rather than from the pyrolysis of pure rubbers. The removal percentages for the ash and sulfur of PR are 98.33% (from 13.98 wt % down to 0.24 wt %) and 70.16% (from 1.81 wt % down to 0.54 wt %), respectively, in the entire process. The ash was mainly composed of metal oxides, sulfides, and silica. The surface properties, porosity, and morphology of the PCB were all close to those of N326. Therefore, PCB will be a potential alternative of N326 and reused in tire manufacture. This route successfully upgrades PR from waste tires to the high value-added CCB and greatly increases the overall efficiency of the waste tire pyrolysis industry.

Synthesis, characteristics and evaluation of antioxidant activity of [1-(tannin-ether)-ethyl]stearate.

The [1-(tannin-ether)-ethyl]stearate (TEES) was synthesized by two-stage process successfully. 1-Chloroethyl tannin ether (CTE), as an intermediate, was initially prepared with tannic acid (TA) and paraldehyde. Then, the TEES was synthesized by sodium stearate and CTE in the presence of FeCl3-PEG-400 as phase-transfer catalyst. Synthetic conditions were optimized. The structural characteristics of TEES were analyzed by FTIR, 1H NMR and UV-vis techniques. And the thermal stability of TEES was investigated. Moreover, the antioxidant activity of TEES for linseed oil was evaluated and compared with other substance such as TA and butylated hydroxyanisole (BHA). The results showed that the yield reached 88.19 wt% (theoretical value: 88.80 wt%, relative deviation: 0.80 ± 0.34%) under the optimized condition, in which the ratio of TA: FeCl3: PEG-400 was 1 g: 0.09 g: 0.693 mL, the reaction temperature and time was 75 °C and 240 min, respectively. The antioxidant activity of TEES was higher than TA and comparable to BHA in linseed oil. The POV of oil samples with TEES, TA and BHA were 63.4, 201.3 and 84.2 meq/kg after 20 days, respectively. The reason of this was relate to the better oil solubility of TEES and its unique structure. More importantly, the interaction between the TEES and SC was weaker than that of TA and SC by the fluorescence experiment.

A novel route to utilize waste engine oil by blending it with water and coal.

Coal-oil-water slurry (COWS) synfuel can be prepared successfully by waste engine oil (WEO), water and coal in the existence of Tween 80 and SL. The effects of coal type, coal particle size distribution, and WEO blending proportion (α) on the slurryability of COWS were investigated, and certain essential properties, such as slurryability, rheology, thixotropy, and stability of COWS were examined. The results show that the maximum coal content of COWS decreases with an increment in α, ranging from 60wt.% at α=0 to 48wt.% at α=15wt.%. The apparent viscosity of COWS becomes high when the amount of WEO is increased for the same coal content. The lower heating value (19.15kJ/g) of 48wt.% COWS (α=15wt.%) is equivalent to that of CWS with 67.88wt.% coal. The mass ratio of separated supernatant to oil-water emulsion for COWS with 49wt.% coal decreases by 1.12% while the amount of WEO is increased to 15wt.% from 10wt.%. COWS exhibits the non-Newtonian pseudoplastic fluid behavior. Its pseudoplasticity and thixotropy are also promoted as the coal content of COWS is increased. And the dispersion and stabilization mechanism of COWS is discussed.

[Effects of glycerol on the spectral properties of sodium caseinate].

Although the immigration of water molecule, and diffusion and traversing of oxygen can be prevented by the edible film prepared through sodium caseinate, which plays a good protection role for the food, the strong hydrophilicity makes its watertightness and mechanical properties become inferior. Because the toughness and water resistance of SC films can be enhanced by glycerol (G) as an additive, it is necessary to elucidate the interaction between G and SC through the spectral characteristics such as fluorescence spectra, infrared spectra and UV spectra. The results show that the fluorescence intensity of SC decreases due to the addition of G. The binding constant obtained by the double logarithmic regression curve analysis is 1. 127 x 10(3) L . mol-1 and the number of binding sites reaches 1. 161. It indicates that the weak chemical bond is primary between G and SC molecules; From IR the absorption peaks of SC are almost the same before and after adding G. However, there is a certain difference among their absorption intensities. It reveals that the secondary structure of SC is affected, ß folding length decreases, α helix, random coil structure, ß angle structure increases, and the intermolecular hydrogen bond is strengthened; From UV the peptide bond structure of SC is not changed after the addition of G, but the polymer with larger molecular weight, which is formed by non-covalent bond, makes the peak intensity decrease. The research gives the mode of G and SC from the molecular level.

[Synthesis and spectral characteristics of selenium-chelated methionine with hexagon].

Using methionine and anhydrous ethanol as raw material, p-toluene sulfonic acid as catalyst, and benzene as a carrying water agent, methionine ester was first synthesized. Then, selenium-chelated methionine was prepared through the reaction of methionine ester with sodium selenite by a certain proportion, settling and crystallizing at lower temperature. The xi potential of the resultant was determined by micro-electrophoresis, through which the isoelectric point was calculated. Based on the principle of isoelectric point, it was separated and purified. The spectral properties of the resultant were analyzed by infrared spectrum, utraviolet spectrum, X ray diffraction analysis and 1H-NMR, from which we got the information of the resultant structure that has a hexagon composing of sulfur atom of methionine, nitrogen of amine and central selenium ion of four-valence.

[Optimization of enzymatic preparation of glucose 1-phosphate by response surface methodology].

With glucose as substrate, sodium tripolyphosphate as the phosphorus acylating agent, and phosphorylase of Solanum tuberosum as the catalyst, glucose 1-phosphate was synthesized. Based on a three-level, three-variable Box-Behnken experimental design, response surface methodology was used to evaluate the effects of temperature, molar ratio of glucose to sodium tripolyphosphate and time on the production. The structure of the product was confirmed by 1H NMR spectra. The results show that the optimum conditions were as follows: temperature 35 degrees C, molar ratio of glucose to sodium tripolyphosphate 1.35:1 and time 19 h.