Advanced Materials Research Vols. 726-731

Abstract: Pidgeon process is used by more than 300 plants in China to produce magnesium (Mg) metal. Fluorite, ranging 2-3%, is often mixed in raw materials to catalyze the Mg production. The Mg slag from the production then contains F of several mass percent. When the Mg slag is used in construction or treated for recycling, possible F pollutions are of concerns. The present study used slag samples containing F of 0.98-2.15% from an Mg factory in northwest China. Both treatments at 1000-1400°C and leaching tests before and after the treatments were conducted for the slag samples. The study results show influences of the treatments on mineral compositions of the samples, which controlled F contents in both the slag samples and leachates. The results are reported and discussed. Some suggestions are also presented to minimize fluorine pollutions and to improve environmental performances of the Pidgeon process.

Abstract: Okara (soybean curd refuse) is the major byproduct in the manufacture of soymilk and tofu. Okara cannot be used in foods due to its high moisture and poor mouth feel. Relatively high insoluble dietary fibers are the main reason for the poor sensory quality. In this study we used the Viscozyme^TM and Pectinex^TM to degrade the first and second layers of soybean cell wall and transform okara as an ingredient for meat products. Pork burgers incorporated with six different levels of hydrolyzed wet okara (5, 10, 15, 20, 25 and 30%) were prepared and compared with controls (without okara). Cook loss (%), cholesterol content, water holding capacity (WHC), color attributes and sensory evaluation were conducted to evaluate the feasibility of hydrolyzed okara as meat product ingredient. While the moisture contents of raw and cooked pork burger increased with the addition of various percentage okara, the addition of okara reduced the cholesterol content by about 6~56% for raw pork burger and 14~47% for cooked burger. The WHC and cook loss (%) of pork burger were improved by the addition of okara. The addition of okara also increased the pH, L* and, b* values of raw pork burger but did not affect a* value. Significant effects of okara on overall acceptability were observed when the addition of okara was above 25%.

Abstract: Aimed to reduce the impact on the environment about waste liquor of morpholine industry,and to increase the profit of it, in this paper, morpholine synthesis from industrial morpholine residual is discussed and optimized, by the method of pressurized hydrolysis reaction. The kinds and volume of catalyst and system temperature-pressure and other reaction conditions are analyzed and optimized to obtain the best yield rate of morpholine. Experiments suggest that pressurized hydrolysis reaction, using sodium hydroxide as catalyst, could be an efficient method to synthesize morpholine from industrial morpholine residual.

Abstract: Laboratory treatments of a plant EAF slag sample 71686 were conducted using stabilizers containing P₂O₅ and air granulation. The results show that it is necessary to add the stabilizers to increase contents of P₂O₅ from 0.39% to 0.7% for the slag stabilization. By a fast air cooling, most of the granules from the granulation are spherical, with a low internal porosity and dense structure. Content of Fe₂O₃ in the granules increased from 7.92% to 18.4% and FeO decreased from 14.3% to 7.8%, due to an oxidation during the slag granulation. Contents of metal elements, As, Cd, Cr, Mo, Pb, Ni and Zn, in the leachates from the treated slag samples were lower than the limit values for leaching from inert wastes pursuant to Directive 1999/31/EC. The slag samples after the treatments may then be regarded as environmentally friendly to use in construction.

Abstract: The study aimed at phosphorus and nitrogen removal by honeycomb cinder modified with Zinc chloride (ZnCl₂). By bench-scale batch experiments, honeycomb cinders with different modification time and ZnCl₂ dosage were modified and its adsorption capacities were evaluated by methylence blue as the adsorbate. Under the optimal modification conditions, large amount modified honeycomb cinders were prepared to remove the phosphorus and nitrogen from domestic sewage, which different operating conditions of honeycomb cinders dosage, and contact time were considered. The results show that removal efficiencies of total phosphate (TP), orthophosphate (PO₄³-P), total nitrogen (TN) and ammonia nitrogen (NH⁴⁺-N) could reach 89.9%, 96.7%, 18.9% and 23.3% under the optimal conditions, respectively. Modified honeycomb cinders might be an effective and low cost adsorbent for phosphorus removal.

Abstract: The fly ash (FA)/nano-ZnO composite was prepared by chemical precipitation method using waste FA, ZnSO4 and (NH4)2CO3 as raw materials and further analyzed by specific surface area and XRD. effects of important preparation conditions on the dye adsorption capacity of the composite were investigated. The results show that the FA/nano-ZnO composite obtained under optimal conditions of FA/ZnO mass ratio of 1:0.5, reaction and standing 2h at 60°C and calcining time of 3h at 250°C is a high efficient adsorbent and has much more higher adsorption capacities on 4 kinds of reactive dyes, reactive turquoise blue KN-G, reactive brilliant blue KN-R, reactive brilliant red X-3B and reactive brilliant red KD-8B from aqueous solution with 61.64mg/g, 46.36mg/g, 43.27mg/g and 31.18mg/g which are increased about 14, 32, 33 and 32 times than that of FA, respectively.

Abstract: LiFePO₄ was prepared using recovered materials from waste Li-ion battery. The recovered materials after treatment was mixed with Li₂CO₃, Fe (NO₃) ₃·9H₂O and NH₄H₂PO₄ to adjust the Li/Fe/P molar ratio equal to 1.05/1/1. The raw material was mixed with super-p and calcined in muffle to get LiFePO₄ by a solid-state reaction. Optimal conditions were: 700°C, N₂ ambience, 10h, and Fe/C=1/1.5 (mol). The characterization results showed that the product was irregular particles with size 5-10μm and good dispersion. When discharged in the range of 2.2~4.2V, the initial discharge capacity was 141.4mAh/g at 0.1C, 103.1mAh/g at 1C. The capacity retention was 97.2% after 300 cycles at 1C showing satisfactory stability.

Abstract: The rapid growth in end-of-life electronic products in recent years has seriously threatened the environment. While if the renewable resource industry introduced the concept of modern logistics, they will be the best carrier for the activities of reverse logistics. The paper aimed to find out the way for the renewable resource enterprises taking part in the reverse logistics, and how they could cooperate with the Manufacturing Industrial Park, and then form the Regional Eco-Industrial Park. This research took two typical districts of Tianjin Ziya Environmental Protection Industrial Park and Tianjin Economic Technological Development Area for example to discuss the foundation and the management for the renewable resource industry in Tianjin, and built a closed-loop supply chain for end-of-life electronic products recycling.

Abstract: The resources of excess sludge exist in zoogloea and bacteria cells.Excess sludge disintegration technique enables the full release of the organic matter in sludge, so that nutrients, energy and other resources in sludge can be fully recycled, meanwhile, the reduction of sludge solids matter can be achieved.Excess sludge disintegration is necessary preprocessing to achieve the harmlessness, reduction and recycle goal of sludge disposal. This article describes the physical, mechanical, chemical, biological, and the combined sludge disintegration method, as well as the principle, characteristics, research progress, and the main research results of various sludge disintegration method.

Abstract: Effects of parameters including pH value, temperature, absorbent dosage, initial ion concentration, and absorbed time, on the removal efficiency of Ag⁺ from aqueous solution were investigated through single factor experiment. Vinasse before and after adsorption were characterized by IR. The maximum removal efficiency of Ag⁺ on vinasse is 97%. The equilibrium sorption is well demonstrated by Freundlich isotherm model.