SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confrrmed by elemental analysis and FI‘-IR spectra analysis. The adsorption properties of sulthydryl chitosan for Cu(Ⅱ ), Cd(Ⅱ ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ) and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.     

A novel high-resolution small ion spectrometer to study ion nucleation of aerosols in ambient indoor and outdoor air

An electrically based ion spectrometer is described, capable of measuring particle sizes and mobilities from molecular ions (small ions) to aerosol particles across a size range of 0.4 to 30 nm in diameter. It consists of a single cylindrical capacitor divided into three electrically insulated sections. The current arriving at the central section is measured by an electrometer and represents the ion flux over a known range of mobilities determined by the applied voltage. The applied voltage is scanned in steps to measure the ion fluxes over a large number of overlapping mobility ranges. The recorded signal and the response function of the instrument are unfolded using a maximum entropy procedure to give a high-resolution measured mobility spectrum. The maximum entropy approach offers a considerable improvement over traditional aspiration collectors and can approach the resolution of a drift tube system. In this way, the spectrometer successfully overcomes the diffusion limit to small ion resolution. Illustrative spectra are shown, demonstrating for the first time the presence of some resolved structure within the small ion spectrum at the highest mobilities. It is demonstrated that the actual mobility spectrum of small ions falls in the range 0.8–2.0 × 10⁻⁴ m² V⁻¹ s⁻¹. This represents a narrower range than that previously measured which is attributed to improved spectral resolution in the present work.     

Sources, input pathways, and distributions of Fe, Cu, and Zn in a Chesapeake Bay tidal freshwater marsh

Tidal freshwater marshes exist at the interface between watersheds and estuaries, and thus may serve as critical buffers protecting estuaries from anthropogenic metal pollution. Bi-weekly samples of newly deposited marsh sediments were collected and analyzed for Cu, Zn, and Fe concentrations over 21 months from July 1995 to March 1997 in five distinct habitats at the head of Bush River, Maryland. Bi-weekly anthropogenic metal enrichments ranged from 0.9–4.7. Anthropogenic excess metal loadings averaged over 1996 ranged from 6–306 and 25–1302 μg cm⁻² year⁻¹ between sites for Cu and Zn, respectively. Based on Fe-normalized trace metal signatures, Susquehanna River sediment does not significantly contribute to upper Bush River. Organic matter was found to dilute total metal concentrations, whereas past studies suggested organics enhance labile metal content. Analysis of metal input pathways shows that marsh metals are primarily imported from nearby subtidal accumulations of historic watershed material by tidal flushing. Received: 29 April 1999 / Accepted: 7 December 1999     

工业硅中铝的测定

在 p H～ 5.7六次甲基四胺介质中 ,Al( )与铬天青 S形成紫红色配合物 ,Al( )浓度在每 1 0 0 ml0～ 1 2 0 μg范围内符合比尔定律。在 568nm处曲线线性良好且经过原点。用于工业硅中铝的测定 ,结果满意     

Preparation and Characterization of Hydroxyiron-Montmorillonite Complexes

Iron elementin soil exists mainly in form s of Fe(OH) 2 ,Fe(OH ) 2 and Fe2 (OH ) 2 2 in tropical and subtropical areaswhere p H values are less than7.These hydroxy- Fe ions reactslowly with montmorillonite by intercalation into their inter-layer space and adsorption on their surfaces,and in this wayvarious hydroxyiron- montmorillonite complexes are formed(Cool and Vansant,1998;Wu et al.,1997;Molinared andClearfield,1994) . Hydroxyiron- montm orillonite complexesare assum ed to have…     

青藏高原中部各拉丹冬峰雪冰记录特征

2005年10~11月在青藏高原唐古拉山脉各拉丹冬峰冰川区不同海拔采集了3个雪坑样品,分析结果表明,雪坑中δ¹⁸O和主要离子浓度具有明显的季节变化特征.夏季风期间降水中δ¹⁸O低于其它季节,表明该地区夏季δ¹⁸O的"降水量效应"仍然存在.雪坑中主要离子在非季风期的浓度高于夏季风期.主要离子的相关分析表明,除NH₄⁺、NO₃^-外,雪坑中其它离子浓度之间均存在较好的正相关性.各拉丹冬峰冰川区仍受到南亚季风的影响,但因其位于夏季风影响的边缘区域,其影响程度相对于高原南部较弱;同时也受到大陆性气候的影响,在冬春季节具有较高的粉尘气溶胶沉降.     

The extent and historical trend of metal pollution recorded in core sediments from the artificial Lake Shihwa, Korea

The vertical distribution of trace metals in sediment cores was investigated to evaluate the extent and the historical record of metal pollution over 30 years in the artificial Lake Shihwa in Korea. A marked increase of trace metals after 1980 was observed due to the operation of two large industrial complexes and dike construction for a reclamation project. There was a decreasing trend of metal concentrations with the distance from the pollution source. The enrichment factor and pollution load index of the metals indicated that the metal pollution was mainly derived from Cu, Zn and Cd loads due to anthropogenic activities. The concentrations of Cr, Ni, Cu, Zn, As and Pb in the upper part of all core sediments exceeded the ERL criteria of NOAA. Our results indicate that inadequate planning and management of industrialization and a large reclamation project accomplished by dike construction have continued to strongly accelerate metal pollution in Lake Shihwa.     

复杂金属矿体地震波正演模拟研究-以庐枞罗河-泥河-大包庄矿床为例

地震勘探在金属矿勘查中发挥越来越重要的作用,但复杂的介质结构和矿体形态通常使金属矿地震解释异常困难,为深入研究复杂金属矿体的地震波场特征,有效开展金属矿地震解释,本文以庐枞矿集区的罗河、泥河和大包庄矿床为例,在详细开展物性测量和地质与地球物理建模的基础上,对均匀介质复杂矿体模型、简化矿体模型和随机介质简化矿体模型进行了...     

Temporal and spatial biomonitoring of heavy metals in eastern Aegean coastal waters using Amphibalanus amphitrite

This biomonitoring study presents the spatial and temporal distributions of heavy metals in the soft tissues of a major fouling species Amphibalanus amphitrite living on hard substrate at different sites along the eastern Aegean coast. A. amphitrite has been chosen as a strong candidate for monitoring heavy metals. Sediment and seawater samples were also collected to detect their metal contents in order to gain more information on the environmental conditions and possible bioaccumulation patterns. The physico-chemical characteristics of sampling stations have been measured in order to characterize the sampling area. The order of metal concentrations in barnacles, sediment and seawater decreased in the following order Cu > Fe > Zn > Mn > Cd > Cr > Pb > Hg, Fe > Mn > Zn > Cu > Pb > Cr > Hg > Cd and Fe > Zn > Mn > Cu > Pb > Cr > Cd > Hg, respectively. These results showed that barnacles accumulate Cu in a higher degree than both sediment and seawater. Moreover, metal concentrations in barnacle have the potential for use in any future regulatory framework monitoring and eventually controlling ambient metal pollution levels.