红壤中质子化及铝的溶解与质子缓冲之间的关系

 用平衡实验及动力学实验研究了我国南方4种红壤的表面质子化及铝的溶解与质子缓冲之间的关系.结果表明,由于游离氧化铁的含量、活性及对铝溶解反应位的掩盖程度等与质子化密切相关因素的不同影响,4种红壤的总H⁺消耗量和铝溶解量不同,宁海红壤和嵊县红壤的质子化程度及H⁺的总消耗量大于永春红壤和屯溪红壤;屯溪红壤铝的溶解量最大,宁海红壤铝的溶解量最小.尽管屯溪红壤铝的溶解量最大,但H⁺的总消耗量却最小.当红壤中氧化铁含量较高时,铝的溶解在H⁺消耗中只起次要作用,质子化过程是H⁺消耗的主要途径.     

挥发酚测定中的边界条件初探

4-氨基安替比林萃取光度法测定水样中挥发酚,是环境监测中首选的测定方法.在样品的采集、水样预处理及分析操作过程中,除了严格执行操作技术规程外,还要考虑分析中的关键技术、边界条件等一些因素,以保证实验的顺利进行和分析数据的准确可靠.     

高负荷厌氧生物反应器的三元酸碱缓冲体系特征与调控

高负荷是升流式(Up-flow Anaerobic Sludge Bed, UASB)、内循环厌氧反应器(internal circulation, IC)和厌氧膜生物反应器(anaerobic membrane bioreactor, AnMBR)等厌氧生物反应器发展的趋势,也是实现"沼气升级(biogas upgrading)"的难点.挥发性有机酸(volatile fatty acids, VFAs)和溶解性无机碳(total inorganic carbon, TIC)既是厌氧消化必经的中间产物,又与氨氮等弱碱共同影响高负荷厌氧消化过程的pH变化,并决定着沼气中的甲烷含量.VFAs、TIC和氨氮构成的三元pH酸碱缓冲体系是高负荷厌氧消化"沼气升级"的关键操作条件.本文总结了高负荷厌氧消化过程中pH变化规律和影响,针对不同VFAs/氨氮关系的形成机制,分析了高负荷厌氧消化碳酸盐缓冲体系特征及其对沼气CH_4/CO_2构成的影响.以厌氧膜生物反应器为例,讨论了近年来基于pH在线监测和调控方法、理论模型方面的研究进展,同时对未来的重点研究方向提出展望,以期为今后的高负荷AnMBR研发提供参考.     

南方酸性土壤中汞污染状况调查

通过测量南方酸性土壤中pH值、有机质、硝态氮及汞的含量变化,分析物质间变化关系,了解南方酸性土壤中重金属汞的污染状况,并针对南方酸性土壤的特性提出了污染防治措施及建议.     

A/O工艺曝气量控制及pH和DO的变化规律

对A/O工艺研究了不同运行条件下曝气量对硝化过程的影响,以及好氧区pH和DO浓度的变化规律。发现随着曝气量的增加,平均硝化反应速率提高,平均DO浓度增加,但增加幅度降低。需通过控制曝气量大小,间接的控制硝化反应速率,使出水达标排放。可以应用平均溶解氧浓度和pH曲线上是否出现拐点,来判断反应系统的曝气是否过量、适量或不足。     

含磷酸盐的三氯化铁水解溶液的化学特征

通过对含磷酸盐三氯化铁水解溶液的ｐＨ驰豫，电导率，可见光光谱和不同化学反应活性组分的分布等一系列化学物理性质的表征，说明在ＦｅＣｌ３－ＮａＨ２ＰＯ４－ＮａＨＣＯ３溶液体系中，ＰＯ４＾３参与了Ｆｅ（Ⅲ）的水解－聚合反应，形成了Ｆｅ－ＯＨ－Ｆｅ－ＰＯ４－Ｆｅ结构共同控制溶液性质。使溶液性质发生了从量变到质变的过程，证明ＰＯ４＾３对Ｆｅ（Ⅲ）溶液的水解形态有重要影响。     

山东省城市大气降水pH值观测结果及其初步分析

通过对山东省十七个主要城市2003年大气降水观测数据的统计分析,对大气降水pH值的时空分布特征和酸雨频率进行了分析。结果表明,山东省酸雨主要出现在秋季和冬季;鲁北平原、鲁中南的莱芜地区,胶东半岛地区频率较高。从酸雨与气象条件的初步分析得出,风速越小时,地面风对酸雨的贡献就相对增大;冬季接地逆温的存在为酸雨形成提供了极其有利的条件。文章并从气象角度对酸雨成因机理作了初步的分析。     

THROUGHFALL pH: EFFECT OF PRECIPITATION : TIMING AND AMOUNT1

ABSTRACT: Precipitation, throughfall, and stream pH were measured weekly over a 27-week period in 1982 on the Little Millseat watershed in eastern Kentucky. The average pH values over the study period were 4.3, 4.9, and 6.4, respectively, indicating significant buffering as water moved from the atmosphere, through the deciduous canopy, and through or over the soil to the stream. Regression analysis demonstrated that the timing and amount of precipitation were important factors influencing the pH of the throughfall. Weekly precipitation and the three-week average precipitation were statistically significant variables, explaining 53 percent of the variance in the observed through- fall pH. Precipitation pH was not a statistically significant variable for this watershed and sampling period.     

Human impact on beach and foredune microclimate on North Padre Island,Texas

The microclimate of beach and foredune areas of North Padre Island along the mid-Texas coast was found to be greatly modified by vehicular and pedestrian traffic during investigations made from late fall to early summer 1973–74. The primary effect of human activity on microclimate was expressed as reduced cover and species diversity of the vegetation. As the intensity of human activity increased, elevation, especially of areas near the beach, was decreased, whereas average wind velocities near the ground surface, evaporation, atmospheric salinity near the ground surface, wind-carried sand particles near the ground surface, soil salinity, soil pH, average soil temperature and range in temperature, soil bulk density, and soil-water contents were increased.     

COMPUTER APPLICATION TO DOUBLE-MASS ANALYSIS1

ABSTRACT: Double-mass analysis for checking consistency of a hydrological record is considered to be essential before taking it for analysis purpose. Because of increasing computer application in hydrological analyses, in the present paper, a simple and efficient method for the double-mass checking has been developed. The problem has been formulated in FORTRAN IV language and the basic steps and a computer output of the program are presented in a flow chart and a table.