基于DGT技术的广西碳酸盐岩区稻米镉含量主控因素

为探究广西碳酸盐岩区水稻在地质高背景下影响稻米Cd富集的主控因素,以广西西南部和北部碳酸盐岩区水稻籽粒-根系土壤样品为基础,同时结合梯度扩散薄膜技术(DGT),分析讨论了土壤pH、有机质(OM)、阳离子交换量(CEC)和DGT-Cd等与水稻籽粒ω(rice-Cd)-BCF值的关系,通过主成分分析确定主要因素并建立定量模...     

废旧农膜的回收再生利用技术

废旧农膜的回收利用是关系到农业可持续发展的重要课题。通过对废旧农膜回收利用的几种主要途径的原理和特点的分析，指出了目前我国农用塑料薄膜的回收利用应以回收再生利用为主要发展方向，进一步论述了农膜的再生利用技术方法和前景，试验结果表明：将废旧农膜再生成塑料颗粒或农膜是值得肯定的一种有利可图的方案。     

Distribution, risk and bioavailability of metals in sediments of Lake Yamdrok Basin on the Tibetan Plateau, China

Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed, but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of metal bioavailability data. In this study, distribution, potential risk, mobility and bioavailability of metals in sediments of Lake Yamdrok Basin in Tibet of China were explored by combined use of total digestion, sequential extraction and the diffusive gradient in thin-films (DGT). Average concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in surface sediments were 31.25, 30.31, 22.00, 45.04, 31.32, 0.13 and 13.39 mg/kg, respectively. Higher levels of metals were found near the inflowing rivers. Residual form was dominant in Cr, Ni, Zn, Cd and Pb, and reducible form was dominant in As and Cd. Metals in surface sediments showed a low enrichment degree overall, but Cd and As had higher ecological risk levels than the other metals. Furthermore, there was a larger average proportion of exchangeable form of As (20.4%) and Cd (9.0%) than the other metals (1.7%-3.3%), implying their higher mobility and release risk. Average DGT-labile concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb were 0.5, 4.5, 0.7, 25.1, 60.0, 0.22 and 1.0 µg/L, respectively. The DGT-labile As was significantly correlated with extractable As forms (p< 0.01), suggesting that extractable As in sediments acts as a “mobile pool” for bioavailable As. These results suggest potential risks of As and Cd, especially As, deserve further attention in Lake Yamdrok Basin.     

黑臭河流沉积物磷、铁、硫的DGT同步分析研究

沉积物中磷(P)、铁(Fe)、硫(S)之间存在密切的耦合关系,但大部分研究并未提供直接的原位证据,需要借助高分辨的获取技术才能表征.为了探索三者之间的耦合关系,本文利用Zr O-Ag I DGT和Chelex DGT对东莞市黑臭河流沉积物中有效态P、Fe、S进行了高分辨分析.结果表明:应用DGT技术能够获得黑臭河流沉积物中有效态P、Fe、S的高分辨率浓度分布,并且实验结果可靠,有效地避免了主动采样方法和沉积物空间异质性对P、Fe、S同步分析的影响.各采样点沉积物中有效态P、S在垂向上的空间分布趋势基本相似,部分采样点出现有效态P、Fe、S同步变化的现象,同步获得的微界面浓度分布较好地反映了三者的耦合关系.对P、Fe、S在水-沉积物界面附近的含量分布进行相关性分析,结果表明三者之间具有显著正相关(p0.05),进一步证实了黑臭河流沉积物中也存在P、Fe、S同步释放的现象.大部分样点沉积物-水界面有效态P、Fe、S的扩散通量为正值,表现为由沉积物向上覆水释放P、Fe、S.沉积物中P、Fe、S的耦合释放表明其对黑臭的形成和内源磷释放至关重要.     

Agricultural Application and Environmental Degradation of Photo-Biodegradable Polyethylene Mulching Films

Photo-biodegradable polyethylene (PBD-PE) films containing starch have been developed and used in agriculture. They are better able to raise temperature, preserve moisture, and raise yield than common polyethylene films, and they can be degraded environmentally after finishing these functions. The photo-biodegradation induction periods of four kinds PBD-PE films range from 46 to 64 days, which basically satisfies the needs of agricultural cultivation. All PBD-PE films can be degraded to Stage V, in which almost no film exists on the surface of the ridges 2–3 months or so after the induction periods. The PBD-PE films buried in soil have also good degradability.     

Photocatalytic degradation of organochlorine compounds using TiO2 supported on fiberglass cloth

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用胶片生产中的含铝废渣生产高效净水剂聚合氯化铝的研究

介绍了利用胶片生产中含铝废渣生产高效净水剂聚合氯化铝的工艺技术路线。结果表明 ,该产品技术指标符合国家标准 ,且生产过程具有工艺简单、投资少 ,不产生二次污染等特点。     

Photocatalytic degradation of organochlorine compounds using TiO2 supported on fiberglass cloth

The feasibility of photocatalytic degradation of organochlorine compounds using TiO₂ supported on fiberglass cloth as a photocatalyst was studied. The results showed that 2.0×10^-4 mol/dm³ of dichloroethylene, trichloroethylene and tetrachloroethylene can be completely photocatalytically degraded within a short time under illumination with a 375W medium pressure mercury lamp. The effects of parameters such as illumination time, initial concentration of organochlorine compounds, amount of air flow and concentration of H₂O₂ on the photocatalytic degradation were investigated. The TiO₂ supported on the fiberglass was not easily detached and after 500h illumination there was no significant loss of photocatalytic activity of TiO₂. The passible mechanisms of photocatalytic degradation were discussed.     

空心玻璃微球附载TiO2清除水面漂浮的油层

以空心玻璃微球为载体，采用浸涂法制备出ＴｉＯ２／ｂｅａｄｓ光催化剂．研究了利用ＴｉＯ２／ｂｅａｄｓ光催化剂降解水面漂浮的正十二烷及甲苯的可行性．结果表明，３７５Ｗ中压汞灯照射１２０ｍｉｎ，正十二烷的光催化去除率达９３．５％，光照８０ｍｉｎ时甲苯被完全光催化去除；通入空气有利于正二十烷及甲苯的光催化去除，外加微量的Ｈ２Ｏ２（５．０ｍｍｏｌ／Ｌ）可大大提高光催化去除率，向反应液中加入少量Ｎａ＋对正十二烷及甲苯的光催化去除率无明显的影响．     

疏水催化剂用于水中氚回收的实验研究

本文简要介绍了自制的几种疏水催化剂的主要特性，采用这些催化剂进行了室温下的Ｈ－Ｔ同位素交换实验，初步考察了氢气流速对催化活性的影响。实验表明，催化剂的催化活性较高，能够用于室温下从氚水中回收氚