Organic Nitrogen in Precipitation Across the United Kingdom

The concentration of water-soluble organic nitrogen (WSON) in precipitation has been measured at seven sites across the United Kingdom, over a period of 1–2 years, using protocols developed in a pilot study. Samples were collected over 1–2 weeks in continuously open funnels made of stainless steel, draining to a glass bottle, and were preserved during and after collection by the addition of thymol. After chemical analysis, samples were excluded from the long-term average if they showed signs of contamination (significant concentrations of K⁺ or PO₄ ^3–). Two methods of measuring total dissolved N were used, persulphate oxidation and high-temperature chemiluminescence. The latter generally gave the larger values, and has been used to asses the organic component of dissolved N. The long-term data set confirms the original results from the pilot study - organic N contributes between 24 and 40% to the total annual wet deposition of dissolved N across the United Kingdom. The fraction of WSON was greatest at western sites, and was strongly correlated with ammonium concentrations. However, the seasonal pattern across all sites showed a late spring maximum for ammonium and nitrate, but a late summer maximum for WSON. The magnitude of the contribution of WSON to wet-deposited N has implications for the setting and assessment of critical loads for N deposition.     

铁炭微电解-Fe~（2＋）/K_2S_2O_8降解甲基橙

针对偶氮类有机物废水具有色度大,难降解的特点,以对二甲基氨基偶氮苯磺酸钠（甲基橙）为模拟研究对象,对水体系中铁炭微电解-Fe2＋/K2S2O8降解甲基橙的方法进行了研究。通过正交实验确定出该方法各因素的影响程度,进一步通过单因素影响实验确定该方法的最佳条件是：铁炭微电解填料、FeSO4和K2S2O8投加量分别为300 g/L、1.3mmol/L和0.7 mmol/L,初始pH值为7.0。在最佳条件下,甲基橙COD和色度去除率分别能达到64.7%和68.2%。     

铁炭微电解-Fe2+/K2S2O8降解甲基橙

针对偶氮类有机物废水具有色度大,难降解的特点,以对二甲基氨基偶氮苯磺酸钠(甲基橙)为模拟研究对象,对水体系中铁炭微电解-Fe2+/K2S2O8降解甲基橙的方法进行了研究。通过正交实验确定出该方法各因素的影响程度,进一步通过单因素影响实验确定该方法的最佳条件是:铁炭微电解填料、FeSO4和K2S2O8投加量分别为300 g/L、1.3mmol/L和0.7 mmol/L,初始pH值为7.0。在最佳条件下,甲基橙COD和色度去除率分别能达到64.7%和68.2%。     

二氧化钛悬浆体系中过硫酸盐对苯酚光催化降解的影响

研究了二氧化钛悬浮溶液中过硫酸盐对苯酚的吸附和光催化降解动力学的影响.在过硫酸盐浓度较低的条件下,S2 O2 - 8的加入能有效提高苯酚的光催化降解速率和表观量子产率,UV TiO2 K2 S2 O8体系下的表观量子产率大于UV TiO2 与UV K2 S2 O8两体系下表观量子产率之和;但是,当过硫酸盐浓度较高时,随着S2 O2 - 8浓度的增加,竞争性吸附加剧,二氧化钛表面的苯酚吸附量急剧减少,导致苯酚的降解速率和表观量子产率不升反降,苯酚平衡吸附量与光催化降解速率呈高度一致性.在本实验条件下,当K2 S2 O8浓度为5 0 0mg·L- 1 时表观量子产率达到最大,协同因子达0 3 9.在不同强度的入射光条件下,也能得到相似的结果.此外,讨论了pH值对不同体系TOC去除率的影响,并对在K2 S2 O8存在时TiO2 的光催化机理进行了探讨     

过硫酸钾溶液对测定总氮的影响

通过对过硫酸钾的配制方法,加热时的水浴温度,反应介质条件及其纯度等因素对总氮测定结果影响的讨论,提出了过硫酸钾有效的配制方法及其纯度要求,以进一步提高总氮测定的准确度.