Advanced Materials Research Vols. 726-731

Abstract: Manganese oxides supported palygorskite (MnOx/PG) catalysts used for low-temperature selective catalytic reduction of NO with NH₃ was modified by doping cerium oxide as additive for enhancement of its performance. The effects of doped cerium content on catalysts' activity were investigated. It was found that the NO removal efficiency of Mn8Ce5/PG catalyst was remarkably higher than Mn8/PG catalyst especially at low temperatures, revealing that the addition of cerium oxide effectively enhanced the catalysts' SCR activity. Catalysts were characterized by BET, XRD, XPS to explore the relation between structural properties and increasing in SCR activity via modification. Results showed that the doping of cerium oxide has improved the dispersion of manganese oxides as active species. And furthermore, the stability of surface MnO₂ was also improved which was suggested to be the main reason for the enhancement of catalysts' activity.

Abstract: Corncob xylitol residue was soaked with H₃PO₄ for 16h and carbonized in microwave for 9min to obtain activated carbon. The adsorbing property of the activated carbon was investigated. Results showed phenol could be adsorbed effectively by activated carbon and the optimum adsorbing condition was: 20°C, 2h, pH 3-4. Increasing the amount of activated carbon could adsorb more phenol, and this effect was not apparent when the amount of activated carbon was more than 0.5g when adsorbing 100mL of 200mg/L phenol solution.

Abstract: NH₄⁺-N was choiced as an influence factor for analysis the effect on the laccase activity from the white rot fungus Pleurotus ostreatus and indole degradation. The experiments were performed with different NH₄⁺-N concentration, with a focus on the indole degradation by laccase in the presence of 2,2-Azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) or not. Results showed that NH₄⁺-N had a positive effect on laccase activity and also enhanced the degradation of indole. Meanwhile, NH₄⁺-N was oxidized to NO₂^-.

Abstract: The technology of diesel particulate filter (DPF) is one of the most effective ways to control particulate emission of diesel engine. In this paper, a DPF was installed on a high-pressure common rail diesel engine, which meets China Stage III emission standard (GB17691-2005), to investigate the filtration efficiency of DPF, and its effects on exhaust back pressure, fuel economy, and emissions characteristics of diesel engine by test bench. Results showed that after DPF was installed on the engine, the PM was reduced by more than 90%, while specific fuel consumption and exhaust back pressure were increased by about 5% and 10kPa, respectively.

Abstract: In this paper, a new technology of sintering flue gas desulfurization is proposed. The principle is that some kind of additives is introduced into feed mix, the additives decompose into NH₃ in sintering process during heating, the NH₃ reacts with SO₂ gas to form ammonium sulphate solid particles, the particles are captured as dust by ESP, so the removal of SO₂ in sintering flue gas is achieved. The study results show that the concentration of SO₂ in sintering flue gas decreases gradually with the increase of additive amount, when the specific quantity of additive is 3.02kg per ton mix, the decreasing rate of SO₂ is up to 81.33%(mass). Since sintering dust must be recycled as raw materials, in order to solve the problem of flue gas SO₂ concentration is gradually increasing, the approach of increasing the amount of additive can be taken, or the dust is separately treated for sulfur removal before being used as raw sintering material. The new approach of reducing SO₂ emission in sintering flue gas has advantages of low investment, small occupation area and low operation cost. Moreover, the additive is inexpensive and readily available, so sintering cost is not increased obviously.

Abstract: In order to prevent the loss of microbes, added anaerobic ammonia oxidation to (ASBR) reactor plus membrane as the growth of anaerobic ammonia oxidation bacteria carrier. After 30d cultivate, the activity of anammox bacteria restore to the original level, and improve TN volume load train anammox bacteria. The whole process of NH₄⁺-N and NO₂^--N removal rate has remained at more than 90%.After the activity recovery of anammox NH₄⁺-N, NO₂^--N the ratio of consumption to the NO₃^--N generation finally tends to a certain value (1. 00b 1. 30 b 0. 25).In the process of cultivate, the sludge was gradually changed from black to red brown color .Results show that the ASBR is well suited for anammox enrichment culture of bacteria.

Abstract: A modified Zeolite to be prepared and its performance of removing fluorine from containing fluoride water was reported. Firstly, using zeolite 4A as skeleton, by means of carrying to adsorb Fe^3﹢from containing ferri ions solution, which the zeolite can be modified and the coordination metal center are formed. Based on mechanism of ligand exchange, a new material of removing deeply fluorine from water was got. Secondly , the results show that this modified zeolite has favourable adsorbing capacity for fluorine from water, when fluorine concentration is about 4～25 mg.L^-1, above 99.0% of fluorine can be removed from water. The static saturation adsorbing capacity is 20.1 mg.g^-1, by following conditions:the pH of water range of 5-8; solid-to-liquid ratio of 1:50 and room temperature.Common-ions in water do not make affect to adsorbing fluorine by the zeolite and high selection in process of removing fluorine has been demonstrated.

Abstract: This topic used the method of demulsification-Fenton oxidation to deal with the waste emulsion, and analyzed the influencing factors of COD removal efficiency . Experimental results show that when the dosage of demulsifier is 10g/L ,optimum aeration for 1h , dosage of Fe²⁺ is 500mg/L, the dosage of hydrogen peroxide is 50ml/L, After Fenton reagent has oxided for 1.5 h, the COD removal rate can up to 93.4%.

Abstract: The flocculation effect of poly aluminum ferric chloride (PAFC), diatomit and poly(dimethyldiallyl ammonium chloride) (HCA) which was used alone or cooperated with each other, on the water treatment of the urban landscape waters in Cangzhou was studied. The effect factors included the dosage and proportion of flocculent, the pH and sedimentation time. The experiment results showed that the effect of PAFC cooperating with diatomit or HCA was better than that of the single one. The optimum mass concentration ratio of PAFC to diatomit was 1: 4, a lower mass concentration benefited the removal of turbidity. The turbidity removal effect of PAFC+HCA is the best, with the optimum mass concentration of PAFC 35mg/L, HCA 0.5mg/L ,the best pH=8~9 and the sedimentation time of 1.5 hour, the removal ratio of turbidity was as high as 94%.

Abstract: Nearly all the chlorinated aromatic hydrocarbons are highly hazardous pollutants which do harm to organisms and have to be disposed before entering into environment. The dechlorination mechanisms of mono-chlorobenzene under hydrothermal condition (200°C, 1.5MPa) was investigated in this paper by quantum chemical methods, corresponding experiments was performed to verify the feasibility of the mechanisms. The results of modeling showed hydrated ferric ions reacted with mono-chlorobenzene in redox mechanisms and the activation energy needed in the reduction reaction with [Fe (H₂O)₆]²⁺ is lower than in the oxidation with [Fe (H₂O)₆]³⁺ .The experimental results were consistent with the quantum chemistry calculation of the redox mechanisms.