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101.
浅层地下水矿化度测定方法的探讨 总被引:2,自引:0,他引:2
矿化度是地下水化学成分测定的重要指标 ,在环境监测中 ,用重量法测定矿化度是目前普遍采用的方法。其缺点主要是费时、繁琐、耗电。本研究通过测定洛阳市地下水的电导率 ,分析对比电导率与矿化度的关联 ,并进一步用回归方程确定电导率与矿化度之间的数量关系 ,探索出用电导率法间接测定地下水矿化度 ,具有快速、经济、准确的优点 相似文献
102.
103.
An incubation experiment lasting 111 d was carried out to study the effect of the addition of three clay minerals (Na-bentonite, Ca-bentonite, and zeolite) to soil derived from sewage sludge on water-extractable and exchangeable forms of four heavy metals (Zn, Cd, Cu, and Ni), as well as on soil organic matter mineralization, microbial biomass C and the release of inorganic N. The addition of clay minerals led to a significant decrease in water-extractable and exchangeable forms of heavy metals. The extent of decrease ranged from 14 to 75% for the water-extractable heavy metals and from 12 to 42% for the exchangeable form over the incubation time, as compared with untreated soil. The reduction in extractability of heavy metals was greater due to the addition of Na-bentonite and Ca-bentonite than that due to the addition of zeolite. Addition of clay minerals did not affect any of the following microbiological parameters in the soil: microbial biomass C, organic C (Corg) mineralization, and metabolic quotient (qCO2), and release of inorganic N during the first 3 weeks of incubation. However, as the incubation period increased, these parameters were significantly increased by the addition of clay minerals, especially by the addition of Na-bentonite and Ca-bentonite. This result is explained by a strong reduction in extractability of heavy metals after the addition of Na-bentonite and Ca-bentonite. 相似文献
104.
研究了真空紫外光(VUV,185 am)对于水溶液中五氯酚钠的降解,反应2 h后,初始浓度为10 mg/L的五氯酚钠的去除率达到99%以上,有机氯的脱除率达到70%以上,有效地实现了五氯酚钠的脱毒.溶液初始pH值对五氯酚钠的真空紫外光解有很大影响,pH=10.9时的降解速率常数是pH=3.1时的3倍.表观一级反应速率常数随初始浓度的增加而线性下降.在反应溶液中加入过硫酸盐,可有效提高五氯酚钠的真空紫外光降解速率和矿化速率,过硫酸盐和五氯酚钠摩尔比为24时,降解速率提高3倍,反应4 h后TOC去除率达到95%. 相似文献
105.
土壤氮素矿化研究对从农田生态系统氮素平衡到全球变化和环境问题均具有重要意义。土壤氮素矿化模型的研究方面.目前主要还是以简单功能模型模拟和预测氮素矿化量为主,以双组分一阶动力学模型和一阶-零阶混和动力学模型拟合效果较好;对机理模型的研究还处于探索阶段。从目前的研究看,土壤氮素矿化模型研究应当集中在建立机理模型以阐明主要生态系统的氮素矿化过程。 相似文献
106.
盐分对粉壤土氮转化的影响 总被引:13,自引:1,他引:12
采用室内恒温通气培养法,以北京地区耕作层典型粉壤土为对象,研究盐分对土壤氮素矿化和硝化的影响.实验设置了4个不同盐分〔以ρ(NaCl)计,分别为20,30,50和80 mg/L〕处理和对照处理,并在硝化实验的土壤中加入一定量的(NH4)2SO4,分别在30 ℃恒温培养箱中进行为期105 d(矿化)和49 d(硝化)的培养实验.结果表明:在初期的培养中,低盐分有利于土壤氮素转化,ρ(NaCl)为20 mg/L的处理分别比对照处理的累积矿化量和累积硝化量多18.21%和1.87%;而在长期培养过程中,高盐分不利于土壤氮素转化,且ρ(NaCl)越高抑制越明显,其对土壤氮素矿化和硝化的抑制率达到67.92%和62.58%;土壤矿化势和硝化势随w(NaCl)分别呈指数递减,矿化速率常数和硝化速率常数与土壤中w(NaCl)为二次函数关系. 相似文献
107.
Environmental exposure to arsenic (As) in the Kutahya region of the western Anatolia, Turkey has been reported to cause various
types of arsenic-associated skin disorders (Dogan, Dogan, Celebi, & Baris, 2005). A geological and mineralogical study was conducted to find the sources and distribution of the As. Geogenic (background)
levels were measured in samples collected from various sources in the Gediz, Simav, Tavsanli, Emet, Yoncali, Yenicekoy, and
Muratdagi areas of the Kutahya region. Based on this analysis, we determined that natural sources are a domineering factor
affecting the distribution of As, which was found: (1) mainly in evaporitic minerals, including colemanite (269–3900 ppm)
and gypsum (11–99,999 ppm), but also in alunite (7–10 ppm) and chert (54–219 ppm); (2) in secondary epithermal gypsum, which
has a high concentration of As in the form of realgar and orpiment along fracture zones of Mesozoic and Cenozoic carbonate
aquifers; (3) in rocks, including limestone/dolomite (3–699 ppm) and travertine (5–4736 ppm), which are relatively more enriched
in As than volcanics (2–14 ppm), probably because of secondary enrichment through hydrological systems; (4) in coal (1.9–46.5 ppm)
in the sedimentary successions of the Tertiary basins; (5) in thermal waters, where As is unevenly distributed at concentrations
varying from 0.0–0.9 mg/l. The highest As concentrations in thermal water (Gediz and Simav) correlate to the higher pH (7–9.3)
and T (60–83°C) conditions and to the type of water (Na–HCO3–SO4 with high concentration of Ca, Mg, K, SiO2, and Cl in the water). Changes in pH can be related to some redox reactions, such as the cation exchange reactions driving
the dissolution of carbonates and silicates. Fe-oxidation, high pH values (7–9.3), presence of other trace metals (Ni, Co,
Pb, Zn, Al), increased salinity (Na, Cl), high B, Li, F, and SiO, high Fe, SO4 (magnetite, specularite-hematite, gypsum), and graphite, and the presence of U, Fe, Cu, Pb, Zn, and B, especially in the
Emet, Gediz, and Simav areas, are the typical indicators for the geothermally affected water with high As content. A sixth
source of As in this region is the ground (0.0–10.7 mg/l) and the surface waters (0.0022–0.01 mg/l), which are controlled
by water–rock interaction, fracture system, and mixing/dilution of thermal waters. The high As concentration in groundwater
corresponds to the areas where pathological changes are greatest in the habitants. Arsenic in ground water also effects ecology.
For example, only Juriperus oxycedrus and J. varioxycedrus types of vegetation are observed in locations with the highest concentration of As in the region. Branches and roots of these
plants are enriched in As. 相似文献
108.
109.
铋银氧化物混合物高效氧化降解四溴双酚A的研究 总被引:1,自引:0,他引:1
以Ag NO3和Na Bi O3·2H2O为原料,采用离子交换-共沉淀法制备了铋银氧化物混合物(silver bismuth oxide,BSO),并利用它氧化降解溴代阻燃剂四溴双酚A(TBBPA).研究了制备过程中银铋摩尔比及降解过程中BSO用量对TBBPA降解效果的影响.结果表明,当银铋摩尔比为1∶1,BSO用量为1 g·L-1时,40 mg·L-1TBBPA在7 min内可完全降解,其总有机碳的去除率高达80%.采用离子色谱、气相色谱-质谱联用仪及X射线光电子能谱监测降解过程中TBBPA的变化,发现TBBPA降解过程涉及脱溴、叔丁基碳的断裂和苯环的开环氧化等反应.利用Na N3作为分子探针,发现单线态氧是BSO氧化降解TBBPA的主要反应活性物种. 相似文献
110.
粉煤灰矿化CO2是一种极具前景的减少燃煤电厂CO2排放的技术.然而,目前还缺乏从矿物学角度对碳酸化反应机理的详细认识.本研究选取了3种粉煤灰开展碳酸化实验和矿物学研究,考察碳酸化过程中温度对碳酸化能力及粉煤灰矿物学变化的影响.结果表明,在任一温度下,BJ粉煤灰的碳酸化率均高于YA和LY粉煤灰,这是由于BJ粉煤灰中硬石膏、钙铁石和无定形相等活性矿物相含量较高,LY粉煤灰缺少高活性的钙、镁结晶相.对YA粉煤灰而言,升高温度可显著提高透辉石、尖晶石、黑钙铁矿和方镁石的转化率.在碳酸化YA粉煤灰中同时检测出碳酸钙和碳酸镁/铁,说明除含钙相其他活性元素(Mg和Fe)也参与了碳酸化过程.因此,需要对每个粉煤灰原始材料的矿物学和操作温度进行具体的个案优化,以最大限度地提高固定CO2能力和碳酸化率.结果还表明温度对不同晶型碳酸钙的形成具有重要作用.方解石在低温(40和80℃)下形成,而文石在高温(180和220℃)下形成. 相似文献