Advanced Materials Research Vols. 726-731

Abstract: With the development of the biogas construction, a plenty of biogas slurry was generated. It brought destruction to the environment for the biogas slurry was rich in nutrient components, especially ammonia-nitrogen. Its important that biogas slurry should be treated before it returns to the environment. The zeolite is extensively used in ammonia-nitrogen adsorption for its good adsorption effect. In this study, a modified coal fly ash (CFA) which was produced from raw CFA and had similar structure with zeolite was used as the adsorbent to adsorb ammonia-nitrogen in biogas slurry. The optimum adsorption conditions of modified CAF on adsorbing ammonia-nitrogen in biogas slurry were explored. The results showed that the best conditions were: the mass of modified CAF 1.3g, the initial pH value of solution 5~7 and the adsorption time 20 min.

Abstract: Aqueous solutions of N-methyldiethanolamine (MDEA) are widely used in the sweetening process of sour gases, but the solutions deteriorate due to the contamination in their use process, and the deficiencies of the technologies for the regeneration of disabled solution restrict their development. A vacuum membrane distillation (VMD) technique for the regeneration of MDEA solutions was proposed and experimentally investigated.It is studied the effect of change in solution temperature on its regeneration efficiency and the distillation flux. From the chromatograms it is known that the best temperature for regenerating waste solution by VMD is 70 °C,and the regeneration efficiency can be up to 98% at this experimental conditions.

Abstract: Because of the public environmental awareness growing and Fibrous raw material shortage, waste paper recycling has received widespread attention, increased year by year. Waste paper fiber through the whole process of pulping and papermaking, different production processes and the use of environment, waste paper fiber can occur in many different changes compared with the original fiber, accordingly the paper properties change.In this study, a high-quality aspen high-yield pulp (HYP) was used to improve the Waste paper pulp properties at the laboratory scale.The results indicate that adding 25% aspen HYP into unrefined or refined Waste paper fiber can minimize many of the drawbacks associated with Waste paper fiber: improving its drainage, bulk, and opacity. And addition of a small amount (about 1%) of cationicstarch can also significantly increase the tensile index of OCC.

Abstract: The calorific value of coal gangue is an important indicator to assess its quality for comprehensive utilizations. Although the heating values can be measured experimentally with a Bomb calorimeter, an easier and faster approach within an acceptable tolerance is in great demand. Herein, we use an alternative approach to estimate the heating value based on proximate analysis data, which are measured under the instruction of GB/T 212-2008. The lower heating values of coal gangue samples we collected range from 2307 to 8309 kJ/kg, which are key information for the use of coal gangue in principle. We conclude that the sample with calorific value of 8309 kJ/kg can be used as formal fossil fuel; another sample of 5799 kJ/kg can be used for thermal power generation, while the other four are not worth for fuel.

Abstract: In this study, with iron ore tailing as an alternative to clay, three belite cement clinker samples were prepared in a muffle furnace at 1400°C for 10, 20 and 30 minutes respectively. And calcium sulphate and calcium fluoride were used as composite mineralizer with attempt to decrease clinkering temperature and improve hydraulic activity of dicalcium silicate. QXRD analysis shows that the major mineral components of the clinker are dicalcium silicate,account for over 80% of clinker, and trace amount of tricalcium silicate and ferrite. Scanning Electron Microscope (SEM) analysis indicates that mineral grains were growing with the prolonged soaking duration. EDS analysis identified that C₂S has a Ca/Si ratio varying from 2.07 to 2.32. And XPS analysis shows substantial amount of S and F atoms indented on clinker surface. Using 4×4×16cm mortar specimen, the mechanical strength of belite cement with 5% gypsum addition was investigated based on Chinese National Standard. The testing results show that three belite clinkers give very promising strength development at early ages, and very high strength gain was achieved at 28 days. In addition, this belite cement has a Lime Saturation Factor (LSF) of 0.76, which make it have potential for significant CO₂ emission reduction. Also, more than 35% iron ore tailing was exhausted for producing unit ton of belite cement clinker. High utilization rate leads to not only mineral waste exhaustion, also environmental improvement.

Abstract: Phenol is hardly gasified in supercritical water (SCW) under the temperature 450 °C, at which cleavages of aromatic ring occur difficultly. Partial oxidative gasification provides a potential way to remove phenol for hydrogen at those temperatures. The results showed that even O₂ was less than the required amount for complete oxidation by stoichiometry, effective gasification of phenol in SCW was took place. About 76 % of phenol was removed and 2.7 mol/mol of hydrogen was produced with Na₂CO₃ as catalyst at 180s, O/Phenol 7.5, 450 °C and 24 MPa. The process also indicated partial oxidation of phenol produced some opening-rings products such oxalic and maleic acid, which were slowly gasified. Specifically, at lower O/Phenol ratios, the gasification reaction was predominant which led higher yields of H₂, while at higher O/Phenol ratios, the oxdication predominated, which increased the amount of CO₂ with less H₂.

Abstract: To develop a garbage recycling system, kitchen refuse, a rich and very cheap source of nutrition, was used to produce lactic acid, a raw material for producing biodegradable plastics. The orthogonal experiment shows the highest lactic acid concentration is achieved under the following fermentation conditions: inoculating spore suspension of rhizopus oryzae AS 3.819 of 10%, culturing seed for 17 h, and adjusting fermentation medium to PH8.

Abstract: In the research, the duck farm cushion and organic waste of duck hatching plant and slaughter and processing plant were used as compost materials, single factor 4 levels 3 replications design was carried out. Effects of adding different doses (0%, 0.35%, 0.40%0.40%, 0.45%) of microorganism agent (consisted of thermophilic Bacillus and Serratia) on compost physicochemical indexes including temperature, moisture content, C/N, germination index, total N, total P, total K, available N, available P, available K, and the enzymic activities including urease, cellulase, dehydrogenase, catalase and protease. There were four treatments in this experiment, three was with adding different doses (0.35%, 0.40%, 0.40%, 0.45%) of microorganism agents, one was without adding microorganism agent (control). The results showed that, adding microorganism agent treatment had faster temperature rising, higher temperature and longer high temperature duration than control. At the end of composting, C/N of those with adding microorganism agent were significantly lower than control (P<0.05), germination index, total N, total P, total K, available N, available P, available K were significantly higher than control (P<0.05). Urease, dehydrogenase, Catalase and protease activities were significantly higher than control (P<0.05), however, those with adding microorganism agent were not significantly higher than control (P>0.05).Enzyme activity of experimental treatments and the physicochemical index shows a good correlation. In conclusion, adding 0.35% microorganism agent was optimum for composting in this research.

Abstract: Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).

Abstract: Ion exchange method was used to remove the sodium ions from the mother liquor of sodium fluorosilicate in this study. Some experiments were done at different conditions of the amount of 732 resin, reaction temperature and time. At the same time, the regeneration method of 732 resins and the effect of removing sodium ions of the regenerative resins were investigated either. The optimum conditions were obtained. The result indicated that ion exchange method was feasible. And the resins could be regenerated and reused for many times. Ion exchange method was pollution-free and low cost in the treatment process of mother liquor of sodium fluorosilicate.