全文获取类型
收费全文 | 211篇 |
免费 | 28篇 |
国内免费 | 183篇 |
专业分类
安全科学 | 18篇 |
废物处理 | 22篇 |
环保管理 | 17篇 |
综合类 | 206篇 |
基础理论 | 39篇 |
污染及防治 | 117篇 |
评价与监测 | 2篇 |
社会与环境 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 14篇 |
2015年 | 25篇 |
2014年 | 24篇 |
2013年 | 55篇 |
2012年 | 42篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 25篇 |
2008年 | 16篇 |
2007年 | 25篇 |
2006年 | 21篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有422条查询结果,搜索用时 15 毫秒
161.
养猪废水的吸附-过滤法初级处理试验研究 总被引:2,自引:0,他引:2
以实际养猪废水为对象,采用吸附-过滤法进行预处理,研究稻草滤料和稻草-沸石双层滤料在不同滤速下对养猪废水中CODCr、氨氮和磷的去除效果.结果表明,稻草-沸石双层滤料对CODCr、氨氮和磷的去除效果明显优于稻草滤料.以稻草-沸石双层滤料为过滤介质时,5 m/h的滤速下,CODCr、氨氮和磷的最大去除率分别达47 9%、72 9%和50 1%.研究表明,吸附-过滤预处理不仅能去除养猪废水中的CODCr、氨氮和磷,还能去除一定量的小分子有机物和臭味,同时附着大量固体有机物的稻草和吸附有氨氮、磷的沸石经过处理后可作为土壤改良剂或肥料,从而实现了农业固体废物的资源化利用. 相似文献
162.
Haruhiro Ino Yoshihisa Matsumoto Ryo Takahashi Kazukiyo Takami Junya Nishino Masaaki Itoh 《Journal of Material Cycles and Waste Management》2008,10(2):129-133
H-ZSM-5 zeolite-supported gallium oxides were studied as aromatization catalysts for polyolefin pyrolysate. The catalysts
were prepared by a conventional physical mixing method with a gallium content of 1.0 and 4.5 wt% and were reduced in flowing
hydrogen at 585°C. To test their activity, a polyolefin sample was pyrolyzed and passed over a heated catalyst layer; the
product was analyzed by gas chromatography/mass spectrometry. A continuous-flow fixed-bed reactor was used for aromatization
of a model gas of polyolefin pyrolysate. For chlorine-free sources at 450°C, the catalyst with only 1.0 wt% gallium exhibited
activity comparable to a gallium silicate catalyst. For chlorine-contaminated sources, the catalyst with 4.5 wt% gallium sustained
catalytic activity for long periods. From the activity test results, it was found that zeolite-supported gallium catalysts
prepared by the physical mixing method are suitable for converting polyolefin into aromatic hydrocarbons. 相似文献
163.
164.
165.
本文讨论了利用煤矸石作原料合成沸石时应注意的问题,对煤矸石的原料特征进行了分析,同时提出了适合合成沸石的煤矸石的性质及要求。 相似文献
166.
提出了一种利用沸石强化SBR生物脱氮的新工艺。试验结果表明,沸石具有强化SBR的生物脱氮功能,水温较低时强化作用更为明显。此外,研究了碱度、进水氨氮浓度等对氨氮去除的影响。 相似文献
167.
提出了一种从钛铁渣中提取大量铝的方法.研究了将钛铁渣酸解液中大量铝合成洗涤助剂用4A沸石的工艺条件,得到了合格的4A沸石产品,铝的回收率约为89%.探讨了导向剂在合成沸石中的应用,并对4A沸石产品的物性进行了表征. 相似文献
168.
Use of zeolitized coal fly ash in the simultaneous removal of ammonium and phosphate from aqueous solution 总被引:1,自引:0,他引:1
Wu Deyi Hu Zhanbo Wang Xinze He Shengbing Kong Hainan 《Frontiers of Environmental Science & Engineering in China》2007,1(2):213-220
Discharge of wastewater containing nitrogen and phosphate can cause eutrophication. Therefore, the development of an efficient
material for the immobilization of the nutrients is important. In this study, a low calcium fly ash and high calcium fly ash
were converted into zeolite using the hydrothermal method. The removal of ammonium and phosphate that coexist in aqueous solution
by the synthesized zeolites were studied. The results showed that zeolitized fly ash could efficiently eliminate ammonium
and phosphate at the same time. Saturation of zeolite with Ca2+ rather than Na+ favored the removal of both ammonium and phosphate because the cation exchange reaction by the NH4
+ resulted in the release of Ca2+ into the solution and precipitation of Ca2+ with PO4
3− followed. An increase in the temperature elevated the immobilization of phosphate whereas it abated the removal of ammonium.
Nearly 60% removal efficiency for ammonium was achieved in the neutral pH range from 5.5 to 10.5, while the increase or decrease
in pH out of the neutral range lowered the adsorption. In contrast, the removal of phosphate approached 100% at a pH lower
than 5.0 or higher than 9.0, and less phosphate was immobilized at neutral pH. However, there was still a narrow pH range
from 9.0 to 10.5 favoring the removal of both ammonium and phosphate. It was concluded that the removal of ammonium was caused
by cation exchange; the contribution of NH3 volatilization to immobilization at alkaline conditions (up to pH level of 11.4) was limited. With respect to phosphate immobilization,
the mechanism was mainly the formation of precipitate as Ca3(PO4)2 within the basic pH range or as FePO4 and AlPO4 within acidic pH range. 相似文献
169.
170.
利用三种无机材料沸石、粉煤灰、石灰对目前常用的粉质粘土+膨润土进行改性,以新鲜垃圾渗滤液作为渗透液,从防渗衬里的渗透系数以及对污染物的衰减能力方面进行了对比实验,对三种无机改性防渗衬里的性能进行了研究。实验结果表明:(1)石灰改性的防渗衬里防渗效果最好,其渗透系数能保持在10-8~10-9cm/s;沸石和粉煤灰改性的防渗衬里渗透系数也能达到10-8cm/s,并且随着实验的进行,渗透系数有所下降;(2)改性后的粘性土防渗衬里对污染质的衰减能力强于改性前:其COD的平均衰减百分比由改性前的68.25%分别升高到72.47%、86.94%和89.64%;对三氮的衰减百分比均有提高;对总铁平均衰减百分比为90%以上,对镉、锌也都表现出良好的去除效果。 相似文献