A membrane filter method for the enumeration of aquatic ammonifiers

A standard procedure for the enumeration of heterotrophic bacteria, utilizing heterotrophic plate count medium (m-HPC), has been modified to allow bacterial ammonifier populations also to be counted. Nessler's reagent was included as an outside indicator to ascertain what portion of the population is capable of ammonification. Typically the ammonifier population varied among aquatic habitats, ranging from 0.08 to 37.0% of the heterotrophic population in river water samples, 0.2 to 10.6% for irrigation water samples, and 1.4 to 3.0% for pond and lake water samples.     

低浓度的NO_3~--N对厌氧系统的影响研究

当含低浓度的硝酸盐的高浓度有机废水中厌氧生化降解时,硝酸盐转化过程中首先发生的是氨化作用;随着水解酸化产生挥发性脂肪酸VFA,硝酸盐开始发生反硝化作用,并越来越明显,逐步占主导作用。整个过程对处理效率产生一定的影响。即便是低浓度的硝酸盐,仍可能对厌氧系统产生影响。     

高级脂肪腈合成工艺技术进展

介绍了目前高级脂肪腈合成工艺技术路线,简述了国内脂肪酸氨化脱水制腈工艺技术研究及开发进展情况,并对发展国内脂肪腈/脂肪胺生产提出了建议。     

Transformation of calcium cyanamide and its inhibitory effect on urea nitrification in some tropical soils

Transformation of calcium cyanamide and its inhibitory effect on urea nitrification was studied in some tropical soils. Three soils, from Onne, Mokwa and Samaru, representing different agro-climatological zones of Nigeria were incubated with calcium cyanamide, urea or a mixture of both for eight weeks at 30 °C and at field capacity moisture content. The recovery of inorganic N (NH ₄ ⁺ plus NO ₂ ^- plus NO ₃ ^- )from calcium cyanamide varied from 64% to 87% in different soils. Most of the inorganic N accumulated was in NH ₄ ⁺ form. Nitrification of the accumulated NH ₄ ⁺ in all the soils was slow.Urea (75 mg N kg^–1 soil) was completely nitrified within a week in the Samaru and Mokwa soils whereas in the Onne soil the rate of nitrification was slow. Addition of CaCN₂ at the rate of 10 mg N kg^–1 soil generally delayed ammonification of urea and nitrification was severely inhibited in all the soils. Addition of CaCN₂ at the rate of 20 mg N kg^–1 soil further reduced the ammonification of urea and completely inhibited the nitrification. High recovery of inorganic N from calcium cyanamide and its effective reduction of nitrification of urea make it suitable source of N for plants in the tropics, provided it is managed to avoid phyto-toxicity.     

天然木质素原料的氨化

研究了天然木质素瓜子壳、核桃壳、杏核壳三种原料化学加氨的影响因素.实验表明,天然木质素原料氨化的反应温度比工业木质素高60℃左右,反应时间延长60～160min,氨化产物含氮量可达到4.95%～6.73%;用过氧化氢作氧化剂比用氧气作氧化剂氨化效率高.     

对叔丁基苯甲腈合成工艺研究

简要介绍了以对叔丁基苯甲酸和液氨为原料两步脱水成腈的工艺路线及反应机理,通过实验确定了温度控制是本工艺操作的关键,并提出采用连续氨化反应,缩短了反应时间,提高了产品的产量及产品的收率。是目前最先进的生产方法。     

蜂窝胞壁厌氧生物滤池处理焦化废水的中试研究

采用新型蜂窝胞壁厌氧生物滤池用于A/A/O工艺处理焦化废水,研究了蜂窝胞壁厌氧生物滤池内COD的去除和氨化效果,以及pH、温度对氨化率的影响情况.结果表明,在进水COD平均为2 370mg·L~(-1),NH_3-N质量浓度为165 mg·L~(-1)的条件下,蜂窝胞壁厌氧生物滤池对COD的去除率平均为37%,氨化率平均为30%,与传统的厌氧生物滤池相比,具有水力负荷高、COD去除率高、pH和温度条件要求不高等特点.再经过后续缺氧和好氧工艺,出水COD和NH_3-N均能够达到污水综合排放标准中的二级标准.     

含尿素和氨的化工废水处理

本文介绍了尿素企业生产废水的处理工艺、处理措施及处理效果,旨在为同类废水处理提供参考。     

风化煤和硼在土壤中对尿素氨化与硝化作用及磷有效性的影响

在实验室培养条件下,研究风化煤和硼在土壤中对尿素氨化与硝化作用及磷有效性的影响。结果表明,风化煤和硼对尿素氨化作用有显著的抑制作用,风化煤对脲酶抑制率为5.7%～14%,硝化抑制率为1.4%～8.5%;硼的脲酶抑制率为5.5%～18.3%,硝化抑制率为1.4%～12.7%;风化煤与硼配合的抑制效果更明显,脲酶抑制率为18.3%～43.6%,硝化抑制率为0.6%～10.6%。在专用肥中添加风化煤能使土壤中磷的有效性提高8.2%～23.6%。     

Optical Properties of Nanocrystalline GaN Films Prepared by Annealing Amorphous GaN in Ammonia

Nanocrystalline GaN films were prepared by thermal treatment of amorphous GaN films under flowing NH₃ at a temperature of 600°C to 950°C for 1 h to 2 h. X-ray diffraction and field-emission scanning electron microscopy confirmed the formation of high-crystal-quality hexagonal GaN films with preferential (002) orientation. The photoluminescence spectrum showed a sharp peak near the band gap emission located at 368 nm and a broad blue peak centered at 430 nm. Five first-order Raman modes near ∼143 cm⁻¹, 535 cm⁻¹, 555 cm⁻¹, 568 cm⁻¹, and 731 cm⁻¹ with two new additional Raman peaks at 257 cm⁻¹ and 423 cm⁻¹ were observed. The origin of these new Raman peaks is discussed briefly.