Advanced Materials Research Vols. 781-784

Abstract: Sorption of Acetazolamide was found to be impacted by clay content and soil solution pH, with higher Kd values for soils with higher clay content and higher Kd values as the pH increased. Sorption data on soils were well fitted with Freundlich model (R² > 0.98). The kinetics of adsorption of Acetazolamide has been discussed using four kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model. The pseudo-first-order model and the pseudo-second-order model were both used to describe the kinetics data, and the pseudo-second-order model could describe the sorption behavior of Acetazolamide well.

Abstract: Ultrasonic-assisted extraction of lead from red soil using EDTA was investigated, the experimental result was compared with that of oscillation extraction to evaluate the performance of ultrasonic-assisted extraction. The optimum extraction conditions were 0.006 mol/L of EDTA, 0.006 mol/L of EDTA and 90 min of ultrasonic-assisted extraction or 240 min of oscillation extraction. Under the optimum extraction conditions, the extraction rate of 76.33% and 74.30% was obtained for ultrasonic-assisted extraction and oscillation extraction, respectively. The ultrasonic-assisted extraction could shorter the extraction time with a improved extraction rate effectively.

Abstract: The influence of membrane type on the permeate flux in microfiltration of two sorbents Bentonite a natural sorbent, montmorillonite based clay and Lewatit S1468 a synthetic sorbent, styrene-divinylbenzene based copolymer was studied. Two types of membranes, single-and multi-channel, both asymmetric inorganic ceramic membranes based on α-Al₂O₃, were used. The experimental data were obtained by continuous microfiltration equipment. According to the results use of multi-channel membrane has more advantages higher permeate flux, lower energy consumption, and lower flow rate than disadvantages longer time period to reach the steady state and higher pressure loss.

Abstract: Characteristics of litter decomposition and carbon and nitrogen release were comparatively studied under meadow, typical and desert steppe ecosystems. The results showed that litter under meadow ecosystem had the highest decomposition rate constant of biomass, percentage of carbon, nitrogen and cellulose loss than that under typical and desert steppe ecosystems. Analysis of variance showed that there were obvious significant differences in decomposition rate constant of biomass, percentage of carbon, nitrogen and cellulose loss of litter among three grassland ecosystems. Stepwise regression analysis showed that annual average relative humidity played significant or very significant impact on decomposition rate constant of biomass, percentage of cellulose, carbon, nitrogen loss under three grassland ecosystems. Therefore, litter decomposition and nitrogen release was mainly influenced by precipitation under different grassland ecosystems.

Abstract: BCR three-step extraction method was used to evaluate the speciation of lead in red soil, The result showed that the percentage of bound to carbonates, bound to Fe-Mn oxldes speciation, bound to organic matter speciation and residual speciation are 31.39%, 23.75%, 22.53% and 22.26%, respectively. The bioavailability of lead in red soil was evaluated based on BCR speciation, 77.74% of total bioavailability speciation was observed.

Abstract: Extraction behaviour of copper from Yunnan red soil by EDTA and citric acid were investigated. The influencing factors of EDTA and citric acid extraction were obtained. The EDTA and citric acid composite extraction for copper was also tested. The result showed that the extraction of copper for the system of low concentration citric acid (0.003 mol/L EDTA+0.05 mol/L) can reach to 64.8%, which is very close to that for thesystem of high concentration citric acid (0.003 mol/L EDTA+0.1 mol/L citric acid) (64.9%), and is high than that for 0.01 mol/L EDTA (61.1% )and 0.1 mol/L citric acid (61.2%).

Abstract: Sea water joining diesel was selected to prepare simulated marine oil pollution. With the target of removing diesel from seawater, the influence of various factors on the laccase-catalyzed degradation process was discussed. The experimental results show that the laccase-catalyzed degradation process was significantly affected by laccase dosage, reaction temperature, reaction time, pH of the solution and initial concentration of diesel in the oily wastewater. A systematic optimization study was carried out through a orthogonal test on the basis of the results of the single-factor experiments,and the optimum reaction conditions of laccase catalytic degradation diesel pollutants in seawater was determined. The results indicate that under the conditions of diesel initial concentration of 0.1g/L, laccase dosage of 8mg/L, pH value of 6, the reaction temperature of 25°C and the reaction time of 4h, laccase catalytic degradation rate of diesel pollution can be up to 63.85%.

Abstract: This paper provides a pretreatment method for ore leaching solution by adding an agent level of hydrogen peroxide. Pretreatment temperature, agent level of hydrogen peroxide and pretreatment time were investigated. The results show that relative standard deviation of copper or iron in ore leaching solution determined by iodometry is less than 1.00% with good accuracy and precision under the following conditions: pretreatment temperature of 60°C, agent level of hydrogen peroxide 1.0mL, pretreatment time of 30 minutes. This pretreatment process is simpler, faster, easier to control, and less environmental pollution comparing with the traditional pretreatment.

Abstract: Perfluorinated compounds (PFCs) have been detected in various environmental media in the world, and it is caused widespread concern because its persistence and dangers on the environment and the organism. However, little attention has been paid to their distribution in surface soils. Soils are the main sink for PFCs. In this study, a method was developed for the analysis of nine perfluorinated compounds in surface soils, including eight perfluorinated carboxylic acids and two perfluorinated sulfonic acids. Concentrations of perfluorinated compounds were determined using UPLC/MS/MS. The result shows that PFCs are widespread occurrence in surface soils in study areas.

Abstract: Recently determination of harmful elements in fertilizer has been paid growing attention. The determination method of cobalt in fertilizer by Wavelength Dispersive X-ray Fluorescence Spectrometry (WD-XRF) is developed. The calibration samples are made of blank compound fertilizer to simulate the matrix. The sample covered with microcrystalline cellulose is pressed at 35t for 60s, and cobalt content is determined by WD-XRF. This method has a good repeatability and accuracy with the linearity in the ranges of 0-2000mg/kg. The relative standard deviation is not more than 2.0%. The results obtained from WD-XRF and ICP-AES showed an acceptable agreement. 43 fertilizer samples are collected from 18 countries and determined. The cobalt contents are all not more than 13mg/kg.