Adsorption of heavy metals in mine wastewater by Mongolian natural zeolite

AbstractIn the first, Mongolian natural zeolites, whose base components were clinoptilolite, mordenite, and chabazite, were characterized in terms of element content, cation exchange capacity, and the like. Since the molar ratios of aluminum relative to silicon contained in Mongolian natural zeolites used in this study were lower than those of pure zeolites, the natural zeolite samples contained substantial amounts of impurities. The cation exchange capacity of the natural zeolite sample relatively increased with increasing aluminum content in the zeolite sample. Secondly, the batch equilibrium adsorptions of heavy metals, i.e., copper, zinc, and manganese, from model aqueous wastewater by Mongolian natural zeolites were carried. The natural zeolites could adsorb and remove the heavy metals in the aqueous solutions. The precipitation of metal hydroxide affected the results of adsorption in some cases. The saturated adsorbed amounts of the heavy metals estimated by Langmuir equation were almost same with one another, increased with solution pH and with cation exchange capacity of the natural zeolite

Effect of Modification of Mongolian Natural Zeolites on Adsorption of Chromium from Aqueous Solution

Removal of chromium (Cr (III) ) as well as hexavalent chromium (Cr (VI) ) from tannery wastewater at same time by adsorption using Mongolian natural zeolite was studied in terms of the characteristics, modification, and chromium adsorption performance of the zeolite. The cation exchange capacity of the zeolite ranged from 37×10−3 to 144×10−3 eq·g−1. From the results of phase identification and elemental analysis of the zeolite after modification run, the zeolite was not decomposed and was modified successfully. The zeolites modified by Ba2+, Cu2+, and HDTMA-Br could adsorb Cr (III) as well as the unmodified one could. The higher pH gave the higher adsorption ability, similarly to the adsorption of Cr (VI). Consequently, this adsorption method with Mongolian natural zeolite was proposed to remove Cr (III) together with Cr (VI) from tannery wastewater at same time.DOI: http://dx.doi.org/10.5564/pmas.v0i4.49Proceedings of the Mongolian Academy of Sciences 2009 No 4 pp.71-7

Effects of Sterile Ulva sp. Growth Rate on Water Quality Control of Intensive Shrimp Culture Pond in Developing Countries

To control the water quality in the intensive shrimp mariculture pond by uptaking the total ammonia-nitrogen with sterile Ulva sp., the growth rate of sterile Ulva sp. was experimentally measured and the influence of the rate on the water quality control evaluated. The specific growth rate constant of the seaweed increased with the total ammonia-nitrogen concentration, photosynthetic photon flux density and operating temperature. Then the dynamics of ammonia-nitrogen in the modeled culture pond for the intensive shrimp farming in the tropical region were numerically simulated, in which the seaweed was used to uptake ammonia-nitrogen. The seaweed could uptake ammonia-nitrogen effectively during daytime mainly due to the high intensity of sun light, and the total ammonia-nitrogen concentration in the shrimp pond could be kept very low. The required seaweed density to control the total ammonia-nitrogen concentration less than the recommended maximum concentration of 1.0 ⋅ 10–3 kg N m–3 was estimated to be reasonable

Application of Entrainment Velocity Concept for Evaluation of River Morphology: A Numerical Model Study

Conventionally, fine sediment transport is evaluated in terms of advection-diffusion equation of suspended sediment in which the erosion rate of sediment from the bedload layer plays a significant role. The present study aims to evaluate the riverbed evolution and associated morphological changes in fine sediment dominated Bhairab River of Bangladesh by a depth integrated two-dimensional numerical model. The erosion rate of bed sediment has been evaluated by two approaches. The first approach applies the fall velocity of the sediment particle and equilibrium reference sediment concentration. The other employs the entrainment velocity concept. The results obtained from numerical simulations are verified by the field investigations. The results suggest that the riverbed evolution and morphological changes predicted with the entrainment velocity concept show better agreement with the data obtained from the field investigations.</p

Effects of Inhibitory Factor on Uptake Rate of Ammonia-Nitrogen with Sterile Ulva sp. for Water Quality Control of Intensive Shrimp Culture Ponds

Ammonia-nitrogen uptake by sterile Ulva sp. was studied for the control of culture pond water of intensive shrimp farming. The uptake rates were measured by batch and semi-continuous operations, and analyzed with the Michaelis-Menten model of uncompetitive inhibition. For the batch uptake operations, the Michaelis-Menten parameters were estimated, and the maximum rate and Michaelis constants were estimated as 3.4 × 10–2 kg kg–1 h–1 and 5.5 × 10–3 kg m–3, respectively. The inhibitory factor increased with the uptake time and with the decrease of the seaweed density. In the cases of semi-continuous operations, the seaweed could continuously treat with the model farming culture solution. Although the ratio of the seaweed density relative to the rate of ammonia-nitrogen generation should be appropriately adjusted to keep lower inhibitory factor in the seaweed, the ammonia-nitrogen concentration could be maintained at a relatively low level during operation. Then the ammonia-nitrogen uptake by the alga water was roughly simulated and operation with moderate density of the algae in the pond could maintain the ammonia-nitrogen concentration at a sufficiently low level in the shrimp farming pond. The suggested treatment process might be attractive to control pond water quality for intensive shrimp farming

Evaluation of computer-based computer tomography stratification against outcome models in connective tissue disease-related interstitial lung disease: a patient outcome study

Table S1. Lobar visual scores were adjusted using scintigraphic and gas dilution measures of the physiological contribution of each lobe to the total lung volume in health (top row). The figure was divided by the proportion of each lung representing a lobe (16.7%), or in the case of the left upper lobe, which included the lingula, two lobes (33.3%). Table S2. Single determination standard deviation values of visual CT scores for connective tissue disease-related interstitial lung disease cases. Table S3. Patient age, gender, smoking status and measures of pulmonary function indices, CALIPER and visually scored CT parameters and echocardiography data for the four groups of the ILD-GAP index. Data represent mean values with standard deviations. CTD, connective tissue disease; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; DLco, diffusing capacity for carbon monoxide; Kco, carbon monoxide transfer coefficient; TLC, total lung capacity; CPI, composite physiologic index; ILD, interstitial lung disease; GGO, ground glass opacity; PVV, pulmonary vessel volume; TxBx, traction bronchiectasis; PA, pulmonary artery; AAo, ascending aorta; RVSP, right ventricular systolic pressure. Table S4. P values demonstrating differences between automated stratified groups calculated using one-way ANOVA with Bonferroni correction for continuous variables and t-test with Bonferroni correction for categorical variables. ILD, interstitial lung disease; PA, pulmonary artery; Ao, ascending aorta; HC, honeycombing; DLco, diffusing capacity for carbon monoxide; Kco, carbon monoxide transfer coefficient; CPI, composite physiologic index; RVSP, right ventricular systolic pressure. * not significant. Figure S1. CONSORT diagram illustrating the selection of patients for the final study population. ILD, interstitial lung disease; CTD, connective tissue disease; IPAF, interstitial pneumonia with autoimmune features; LCH, Langerhans cell histiocytosis; LAM, lymphangioleiomyomatosis; CT, computed tomography. (DOCX 67 kb

Serial automated quantitative CT analysis in idiopathic pulmonary fibrosis: functional correlations and comparison with changes in visual CT scores

OBJECTIVES: To determine whether computer-based CT quantitation of change can improve on visual change quantification of parenchymal features in IPF. METHODS: Sixty-six IPF patients with serial CT imaging (6-24 months apart) had CT features scored visually and with a computer software tool: ground glass opacity, reticulation and honeycombing (all three variables summed as interstitial lung disease extent [ILD]) and emphysema. Pulmonary vessel volume (PVV) was estimated by computer only. Relationships between changes in CT features and forced vital capacity (FVC) were examined using univariate and multivariate linear regression analyses. RESULTS: On univariate analysis, changes in computer variables demonstrated stronger linkages to FVC change than changes in visual scores (CALIPER ILD:R2=0.53, p<0.0001; Visual ILD:R2=0.16, p=0.001). PVV increase correlated most strongly with relative FVC change (R2=0.57). When PVV constituents (vessel size and location) were examined, an increase in middle zone vessels linked most strongly to FVC decline (R2=0.57) and was independent of baseline disease severity (characterised by CT fibrosis extent, FVC, or DLco). CONCLUSIONS: An increase in PVV, specifically an increase in middle zone lung vessels, was the strongest CT determinant of FVC decline in IPF and was independent of baseline disease severity. KEY POINTS: • Computer analysis improves on visual CT scoring in evaluating deterioration on CT • Increasing pulmonary vessel volume is the strongest CT predictor of functional deterioration • Increasing pulmonary vessel volume predicts functional decline independent of baseline disease severity