Advanced Materials Research Vols. 634-638

Abstract: A novel method for preparation of iron oxyhydroxide materials, involving aqueous precipitation followed by microwave assisted aging is investigated. The produced materials are characterized by XRD, SEM, EDX and TEM spectroscopy and BET analysis. The materials show physical characteristics dependent on preparation procedure. The adsorptive properties of the materials for arsenic are studied by batch adsorption techniques. It is found that the rate of arsenic upload depends strongly on the degree of crystallinity of the materials. The adsorption capacity is approximately 55 mg/g. The physical characterization of the arsenic loaded adsorbents show that the adsorption process modifies the morphology of the materials. Over 4% of arsenic atoms are incorporated into the particle matrix.

Abstract: The wastewater with iron is a threat to health of human and environment. MgO was used to remove iron and the effect of MgO added amount, the reaction time and temperature on the removal of iron ion were investigated. The removal rate of iron ion was more than 99% and the optimal added amount of MgO was 2.5 g/L with reaction time for 40 min at 25 oC. The results of study on the use of MgO as a water treatment reagent to treat wastewater containing iron ion indicated that MgO had an excellent performance to treat wastewater with iron.

Abstract: Dimethyldithiocarbamate precipitation is a secondary resource containing nickel and cobalt, which are formed by adding sodium dimethyldithiocarbamate to purify the neutralized filtrate of pyrolusite reductive leaching process. The extraction of nickel and cobalt from dimethyldithiocarbamate precipitation was investigated using nitric acid as oxidant in dilute sulfuric acid medium in this paper. The effects of concentrations of nitric acid and sulfuric acid, leaching temperature as well as reaction time were discussed. The results showed that high nickel and cobalt recovery could be obtained by analyzing the leaching efficiencies of nickel and cobalt during the leaching process. The optimal leaching condition was 1.47 mol/L H2SO4 and 1.16 mol/L HNO3 for 30 min at 45 °C while using particles smaller than 0.420 mm. And the leaching efficiencies were 98% for Co and 95% for Ni, respectively.

Abstract: nano-sized TiO2 doped with different percentage of N was prepared quickly by sol-gel process，and the photocatalytic properties of degradation dyes wastewaters were studied under stimulant solar light irradiation in the ambient air. Some properties of photocatalysts were characterized by the means of XPS, UV-Vis ,XRD, and degradation loss. The results showed the catalytic activity was the best when the doped of nitrogen was 0.5% at calcinated 400°C，and the degradation of the methylene blue was almost completed.

Abstract: The suitability of Daqing oilfield wastewater disinfection by electrolysis technology was analyzed. The results show that electrolysis disinfection method is applicable to the water quality of Daqing oilfield. The effect of current, wastewater flow, and electrolysis time on the disinfection effect and power consumption was studied. The results show that the disinfection effect is good and economical for Daqing oilfield wastewater when the current is 2A and the flow is 40L/h.

Abstract: The phosphogypsum is a byproduct of the phosphorus chemical industry, which has not high utilization ratio, is the main area of stockpiling and affects the environment and the sustainable development of phosphorus chemical enterprises. Based on the sulfur resources utilization status from the existing phosphogypsum in the article, the use patterns on the phosphogypsum are divided into three types of hot, wet and biological methods, and there are the reviews on the utilization status of the various methods.

Abstract: In this paper, the adsorption of heavy metals by biomass, namely dry garlic stem, an environmentally-friendly and natural adsorbent, were studied．The efficiency of the adsorbent was studied under different experimental conditions by varying parameters such as pH, initial concentration and contact time using batch adsorption technique. The results show that at pH 5.50, room temperature, the adsorption time 90 min and the amount of garlic stem 0.5 g, Co2+ have the maximum adsorption capacity. The maximum adsorption capacity of the Co2+ on garlic stem is 14.9 mg/g. At pH 9.50, the adsorption time 90 min and the amount of garlic stem 0.7g, Cd2+ have the maximum adsorption at the same temperature. The maximum adsorption of the Cd2+ is 20.90 mg/g. At pH 10.0, the adsorption time 150 min and the amount of garlic stem 0.3g, Ni2+ have the maximum adsorption at the same temperature. The dry garlic stem is a efficient adsorbent in removing cobalt, cadmium and nickel from aqueous solution.

Abstract: A new immobilization microorganism (IM) method was built by adding sodium alginate, SiO2 and CaCO3 in gel and cross-linking with saturated H3BO3 aqueous solution with 2% CaCl2 for traditional PVA-H3BO3 method. The modified method was used for preparation IM for hydrogen production from waste water contained organics by sewage treatment plants’ sludge pretreated. The change rate of the IM balls diameter and unit hydrogen production were taken as the primary performance criterion of the IM. The modified IM method for hydrogen production from waste water contained organics was confirmed: 9% PVA and 0.9% sodium alginate for the embedding medium, saturated H3BO3 aqueous solution and 2% CaCl2 for cross-linking agent, and adding NaCO3 adjusting PH, 3%SiO2 and 0.5%CaCO3 for the support packing of IM balls, and the balls diameter of about 3mm. The modified IM balls had unit hydrogen production of 63.3% and total sugar removal rate of 143.4mL/h•L for washing model wastewater from ice cream factory, which contained 2000 mg/L total sugar and 5500mg/L COD, and higher mechanical strength. It were identified that the method could reduce outside surface’s shrink, and improve the homogeneous of inside endoporus structure of modified IM balls, and a similar inside microporosity and outside microporosity by SEM detection.

Abstract: Ammonium molybdate modified bentonite was prepared from bentonite using ammonium molybdate as modified agent, which was used to remove several industrial effluents. It is used in the pretreatment of monosodium glutamate wastewater, slaughtering wastewater and beer wastewater which have high concentration of COD. The suitable reaction condition is ensured and the treatment effects for the treated effluents are compared by ammonium Molybdate-modified Bentonite. The result shows that the ammonium molybdate-modified bentonite is better than other flocculants. The COD removal rate of monosodium glutamate wastewater, slaughtering wastewater and beer wastewater could reach 55.40%, 96.32%, 93.23% respectively. The treatment of slaughtering wastewater is the best and all treated effects meet the pretreatment requirement. Ammonium molybdate-modified bentonite is applied to several industrial effluents in different business. It is a new type flocculant with good flocculation effect and wide application.

Abstract: This study intends to explore the application of treating Acid Purplish Red dyeing wastewater with an inexpensive adsorbent compounded with Mold/Bentonite. It discussed the adsorption conditions and mechanism of Acid Purplish Red through single factor experiments (including dosage, initial concentration, and pH, stirring time and standing time). It also studied the adsorption kinetics and adsorption thermodynamics of this system. The results showed that the removing rate was above 94%, when the dosage of composite absorbent was 10 g/L, pH was nature (5.8), stirring time was 20min and standing time was 1h.The Acid Purplish Red system accorded with Langmuir and Freundlich absorption model, and it fitted Langmuir thermostatic adsorption equation better. And the saturated adsorption capacity can be obtained as 17.63mg/g. The sorption parameters showed that the adsorption of composite absorbent on Acid Purplish Red was easy, the system was monolayer adsorption. While the adsorption kinetic of Acid Purplish Red system fitted second-order kinetics with 78.15mg/g saturated adsorption capacity of Acid Purplish Red, and the adsorption was chemic-sorption.