Advanced Materials Research Vols. 518-523

Abstract: In this study, we investigate the characteristics of activated sludge pretreated with microwave irradiation and the factors influencing the microwave effects. The pretreatment process was carried out using a lab-scale industrial microwave unit (2450 MHz frequency). Parameters such as the dewatering, settling, sludge volume index (SVI₃₀), water percent content, filterability, extracellular polymeric substances (EPS), microbe structure and others, were used to quantify the microwave effects. The SVI₃₀ and specific resistance to filtration (SRF) of sludge treated by 1000W microwave for 40s were reduced by 43.2 and 74.6%, respectively, compared to untreated sludge. The microwave field destroyed the structure of activated sludge, reducing the EPS levels and breaching the microorganism cell walls. Surprisingly, the optimum microwave irradiation time for removing EPS from activated sludge surface is also the optimum time required to improve its dewatering ability. The microwave output power was one of the most important factors for improving the dewatering of activated sludge when all other parameters of activated sludge and microwave frequency were held constant. The absorbed power and absorb ratio both increase with the output power of microwave, and absorb ratio of 1000w microwave reaches 21.93% in this study.

Abstract: Sediments have a significant influence on the overlying water, and phosphorus (P) release from sediments is an important source for the lake eutrophication, particularly in shallow ones. To better understand the mechanisms of eutrophication, lakes impacted by urbanization at varying levels were investigated. The results showed TP increased continuously from the sediments of eutrophic lake, and released more with higher temperature. While phosphorous could process adsorption and desorption from sediments of mesotrophic lake. It suggested that the sediments of eutrophic lake could be the inner source of phosphorous.

Abstract: A low-cost adsorbent was prepared simply by phosphorylating bagasse. The materials were characterized by Fourier Transform Infrared (FT-IR). Batch adsorption studies were carried out for Cu (II) ions adsorption at different initial concentrations. The pseudo-first-order, pseudo-second-order and the intra-particle diffusion models were used to analyze the kinetic data. The results revealed that the pseudo-second-order model generated the best agreement with the experiment data with the correlation coefficients greater than 0.999 for the adsorption systems. The mechanism of the Cu (II) ions adsorption by the phosphorylated bagasse was also discussed. The FT-IR results showed that the bagasse adsorbent has many different functional groups and these functional groups are able to react with Cu (II) ions in aqueous solution.

Abstract: Pesticides play an important role in development of agricultural in China. Pesticides play a significant role in the effective control of diseases, insects, rodents and weeds, the normal supply of agricultural products to protect human direction, but to bring many negative effects on the safety of human health and the environment. Nervous system is susceptible to pesticides. Many pesticides have neurotoxin effects, could damage including cortex, hippocampus, striatum, including a large number of central nervous system. The paper made a brief overview on the toxicity of pesticides on nervous system research.

Abstract: Pesticides poisoning is a clinical and social problem the whole world concerning about. There is an association between agricultural work and brain cancer mortality in the world. It also suggests that pesticide exposure may play a role in such risk. We made a review on pesticides cause cancer of the mechanisms, including mechanisms of pesticides on cytotoxicity, inflammatory cytokines, and so on.

Abstract: Pesticides are currently used in China, the most toxic pesticides, pesticide use in China currently accounts for more than 80% of the volume, it is through the respiratory tract, skin and mucosa and digestive and other ways to absorb and rapidly cause poisoning. Chinese herbal medicine effective components have alleviated the toxic effects of pesticides, and has been widely used in clinical. The paper made a brief overview on protection of organ on medicine for pesticide poisoning research.

Abstract: The feasibility of heap bioleaching recovery of uranium from the one Uranium Mine deposit uranium-bearing waste ore, located in south of China, were investigated. A 4500 ton industrial heap was constructed in the waste ore dump site. The waste ore sample was crushed to -25 mm, the ore uranium grade is 0.0211%. After 146 days of performance, the slag uranium leaching rate was 55.92% that calculated by its residue has been recovered, content of uranium in residue was 0.0093%, the acid consumption rate was 2.69% by ore weight. The study has proven that recovery uranium from uranium-bearing waste ore using heap bioleaching is feasible.

Abstract: The effects of the supply voltage, water flow rate, concentration of inlet SO₂ and Fe²⁺ in liquid phase on the desulfurization efficiency were investigated by corona discharge with liquid phase on the condition of DC discharge and pulse discharge. The experimental results showed that the desulfurization efficiency increased with the increasing of the supply voltage, water flow rate, and concentration of Fe²⁺. However, the desulfurization efficiency was nearly unchanged with the increasing of the initial concentration of SO₂. The desulfurization efficiency in pulse discharge was better than that of the DC discharge on the same condition, and the highest desulfurization efficiency could be more than 99%.

Abstract: Introduced the current situation of coal slurry difficult sedimentation because of clay easily expansion and hydration to form colloidal suspensions. Experiments of suppressing montmorillonite using several different electrolyte solution was done. The results show that KCl solution can inhibit expansion and hydration of montmorillonite and improve its sedimentation effect significantly and reduce the amount of flocculant greatly. After raw coal sedimentation comparative test, the results show that washing coal by KCl solution can indeed promote coal slurry sedimentation effectively, and the dosage of flocculant is only about 2.5% that of water washed coal.

Abstract: Dry water (DW) is a powder composed of hydrophobic silica surrounding tiny water droplets. It’s recently demonstrated to be an effective medium for storage methane in a hydrated form. But the recyclability of DW is not so clear at present. Here we used a dedicated pressure cell to form four dry water methane hydrates samples (DW-MH), corresponding to four cycle-types of hydrate formation and dissociation, to investigate the reuse of dry water. The results show that part of water escape from DW and become “free water” after DW-MH is dissociated. The free water is hard to form hydrate during the next cycle of hydrate formation. As a result, the gas storage capacity of DW-MH decreases dramatically as the using times of DW increases.