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131.
Adsorption kinetics of methyl violet onto perlite   总被引:11,自引:0,他引:11  
Doğan M  Alkan M 《Chemosphere》2003,50(4):517-528
This study examines adsorption kinetics and activation parameters of methyl violet on perlite. The effect of process parameters like contact time, concentration of dye, temperature and pH on the extent of methyl violet adsorption from solution has been investigated. Results of the kinetic studies show that the adsorption reaction is first order with respect to dye solution concentration with activation energy of 13.2 kJ mol(-1). This low activation energy value indicates that the adsorption reaction is diffusion controlled. The activation parameters using Arrhenius and Eyring equations have been calculated. Adsorption increases with increase of variables such as contact time, initial dye concentration, temperature and pH.  相似文献   
132.
Environmental Science and Pollution Research - More than any other nations, the crude oil–exporting countries and especially the Organization of the Petroleum Exporting Countries (OPEC) are...  相似文献   
133.

Organisms are increasingly exposed to ultraviolet (UV) rays of sunlight, due to the thinning of the ozone layer and its widespread use in sterilization processes, especially against the SARS-CoV-2 virus. The present study was conducted with the purpose of evaluating the damages of UV-A and UV-C radiations in Allium cepa L. roots. The effects of two different types of UV on some physiological, biochemical, cytogenotoxic, and anatomical parameters were investigated in a multifaceted study. Three groups were formed from Allium bulbs, one of which was the control group. One of the other groups was exposed to 254 nm (UV-C) and the other to 365 nm (UV-A) UV. Growth retardation effect of UV was investigated with respect to germination percentage, total weight gain, and root elongation, while cytogenotoxicity arisen from UV exposure was analyzed using mitotic index (MI) and chromosomal aberration (CA) and micronucleus (MN) frequency. Oxidative stress due to UV application was investigated based on the accumulation of malondialdehyde (MDA) and the total activities of superoxide dismutase (SOD) and catalase (CAT) enzymes. Also, anatomical changes induced by UV-A and UV-C were analyzed in root meristematic cells. UV treatments caused significant reductions in growth-related parameters. Both UV treatments caused a significant increase in MDA levels and induction of SOD and CAT enzymes in root meristematic cells. A decrease in MI and an increase in the frequency of MN and CAs were observed in root tip cells, indicating the cytogenotoxic effect of UV application. Anatomical damages such as epidermis cell damage, cortex cell damage, necrotic zones, giant cell nucleus, and indistinct transmission tissue occurred in cells exposed to UV. All of the physiological, biochemical, cytogenetic, and anatomical damages observed in this study were more severe in cells treated with UV-C compared to UV-A. This study suggested that UV exposure triggered growth inhibition, cytogenotoxicity, oxidative stress, and meristematic cell damages in A. cepa roots depending on the wavelength.

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134.
A mediation exercise to resolve the ongoing dispute against these power plant projects at Aliağa was recommended and participated in by the author in 1997. In this article the basis of the continuing environmental concern about the feared impacts of the new power plants, procedure, and results of this mediation are mentioned. The basis of the “energy versus environment” dispute in Aliağa are introduced. Mediation exercise and its end results have been criticized.  相似文献   
135.
A study on the Cr(VI) removal from aqueous solutions by steel wool   总被引:2,自引:0,他引:2  
The reduction of Cr(VI) by steel wool and the precipitation of reduced chromium by CaCO(3) powder and NaOH solution were investigated in continuous and batch systems, respectively. The effects of acid and initial Cr(VI) concentrations, volumetric rate and temperature of solution on Cr(VI) reduction were studied. The results showed that the reduction of Cr(VI), to a large extent, depended on, and increased with, acid concentration. The Cr(III) and iron ions in the reduced solution were completely precipitated by using NaOH solution at appropriate alkaline conditions. It was concluded that CaCO(3) powder could be used as a cheap precipitant for Cr(III) ions. But the iron ions in the reduced solution could not be fully removed by using this precipitant.  相似文献   
136.
137.
《红楼梦》中提及众女子皆如花似玉,似乎在整个大观园中形成了百花齐放,而又百花齐谢的最终结局.究竟是巧合还是刻意?林黛玉的一首《葬花吟》,在喜庆时作为反衬,在没落时作为预言.以之为端倪,此后诗词皆有蕴涵.花,作为《红楼梦》中最常见的意象之一,表达了红颜薄命的伤感以及繁华终将转空头的必然结局.参2.  相似文献   
138.
Concentration of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, Se and Zn were determined in various fish species from the Marmara and Black Sea during 1987 and 1988. Neutron activation analysis, atomic absorption spectrophotometry and X‐ray fluorescence methods were used for analysis. No significant differences between metal values in fish collected in 1987 and 1988 were noted except As and Pb. The As and Pb concentrations in the same species of fish were higher in the eastern Black Sea compared with the other locations. The Hg concentration in Thunnus thynnus muscle ranged from 1.05–3.05 μg/g dry weight. On the other hand, the Hg levels in the other species were found below the detection limit. Comparison of the results obtained with data reported for the Mediterranean Sea shows an agreement in general for most of the metal levels.  相似文献   
139.
白腐菌去除氯代酚动力学研究   总被引:3,自引:0,他引:3  
使用Volterra模型描述 2 ,4-二氯酚体系中白腐菌生长动力学 ,建立氯代酚去除部分偶联型动力学方程 ,描述了生物降解体系中降解菌与目标化合物的反应历程 ,利用动力学方法初步探讨批次反应时生物吸附在氯代酚去除过程中的作用  相似文献   
140.
Concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in macroalgae samples collected from the Turkish Coast of the Black Sea. Certain algae species were chosen among the green, brown and red algae species at Sile and Sinop sampling stations from 1998 to 2000. In general, as regards the influence of the collection sites on the whole metal accumulation, Sinop is considered to be more polluted than Sile. The concentrations of the heavy metals in Cystoseira barbata algae are compared with previous studies in the same stations. The results showed that all metal levels have gradually decreased during past years. At the same time, Cd, Co, Cr, Cu, Fe, Ni and Pb levels in the present study are lower than in Bosphorus and Marmara Sea algae. However, Mn and Zn concentrations are higher than Bosphorus but lower than at Marmara. According to these findings the heavy metal pollution decreased in Turkish Coast of the Black Sea during the years investigated.  相似文献   
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