紫尿酸铵比色法测定大气降水中的钙

在碱性溶液(pH10.4—11.1)中,钙离子与紫尿酸铵生成橙红色的稳定络合物,在500nm处有最大吸收,钙浓度在2.5—25μg/50ml范围内符合比尔定律,表观摩尔吸光系数为1.2×10~4L·mol~(-1)·cm~(-1),桑德尔灵敏度为0.003μg/cm~2。本法快速、准确、可靠,回收率为94—104％。     

LMC低压长袋除尘器在矿热炉烟气治理中的应用

阐述了LMC型低压长袋脉冲喷吹除尘器在矿热炉烟气治理中的成功应用。LMC型除尘器在设计上充分考虑到矿热炉高温烟气温度和粉尘性质对设备的影响,并根据不同烟气温度、粉尘性质及工艺的变化,采用不同配件和材料。     

Endogenous nitric oxide mediates alleviation of cadmium toxicity induced by calcium in rice seedlings

The effect of calcium chloride (CaCl₂) on rice seedling growth under cadmium chloride (CdCl₂) stress, as well as the possible role of endogenous nitric oxide (NO) in this process, was studied. The growth of rice seedlings was seriously inhibited by CdCl₂, and the inhibition was significantly mitigated by CaCl₂. However, hemoglobin (Hb) and 2-(4-carboxyphenyl)-4, 4,5,5-tetramethylimidazolinel- oxyl-3-oxide (cPTIO) weakened the promotion effect of CaCl₂. The results of NO fluorescence localization suggest that growth accelerated by CaCl₂ might be associated with elevated NO levels. The content of Cd, protein thiols (PBT), and nonprotein thiols (NPT) in cell walls, cell organelles, and soluble fractions, respectively, of rice seedlings decreased considerably in the presence of CaCl₂, whereas the content of pectin, hemicellulose 1 (HC1), and hemicellulose 2 (HC2) increased significantly. Elimination of endogenous NO in Cd+Ca treatment could promote the transportation of Cd²⁺ to cell organelles and soluble fractions and increase the content of NPT and PBT in leaves. In addition, transportation of Cd²⁺ to cell organelles and soluble fractions was retarded in roots, the content of NPT increased, and the content of PBT decreased. With elimination of endogenous NO in Cd+Ca treatment, the content of pectin, HC1, and HC2 decreased significantly. Thus, Ca may alleviate Cd toxicity via endogenous NO with variation in the levels of NPT, PBT, and matrix polysaccharides.     

烧结板除尘器在PVC生产中的应用

介绍了烧结板除尘器在电石法PVC生产中的应用；简述了烧结板除尘器的工作原理和特点；通过结合烧结板除尘器在矿石生产线上的应用情况，验证了烧结板除尘器在电石法PVC等行业除尘应用中的优异除尘效率。     

密闭电石炉尾气利用新途径

密闭电石炉尾气具有成分复杂、净化难、热值较高等特点。现有的利用方法存在可选择的成熟技术少、限制条件多等问题。以年产6万吨电石的电石厂为例,进行了技术经济分析,提出了具有分布式能源特征的密闭电石炉尾气利用途径。     

Application of an early warning indicator and CaO to maximize the time–space-yield of an completely mixed waste digester using rape seed oil as co-substrate

In order to increase the organic loading rate (OLR) and hereby the performance of biogas plants an early warning indicator (EWI-VFA/Ca) was applied in a laboratory-scale biogas digester to control process stability and to steer additive dosing. As soon as the EWI-VFA/Ca indicated the change from stable to instable process conditions, calcium oxide was charged as a countermeasure to raise the pH and to bind long-chain fatty acids (LCFAs) by formation of aggregates. An interval of eight days between two increases of the OLR, which corresponded to 38% of the hydraulic residence time (HRT), was sufficient for process adaptation. An OLR increase by a factor of three within six weeks was successfully used for biogas production. The OLR was increased to 9.5 kg volatile solids (VS) m^?3 d^?1 with up to 87% of fat. The high loading rates affected neither the microbial community negatively nor the biogas production process. Despite the increase of the organic load to high rates, methane production yielded almost its optimum, amounting to 0.9 m³ (kg VS)^?1. Beneath several uncharacterized members of the phylum Firmicutes mostly belonging to the family Clostridiaceae, a Syntrophomonas-like organism was identified that is known to live in a syntrophic relationship to methanogenic archaea. Within the methanogenic group, microorganisms affiliated to Methanosarcina, Methanoculleus and Methanobacterium dominated the community.     

电石法聚氯乙烯生产行业的汞污染防治

结合我国电石法聚氯乙烯生产行业的发展现状,提出了采用低汞触媒替代高汞触媒以降低汞消耗、开发高效除汞器以提高脱汞效率、深度解吸废盐酸以解决汞转移问题、深度处理含汞废水以实现综合利用、优化工艺控制以降低汞触媒消耗、改善防护措施以减轻汞扩散等汞污染防治工作的要点。     

CaCl_2-PAC工艺处理酸性高氟废水

以湖南某氟化盐厂排放的酸性高氟废水为研究对象,提出Ca Cl2-PAC处理酸性高氟废水新工艺,确定了最佳工艺条件,并对比了晶种添加前后对除氟效果、沉渣含水率的影响及沉渣中氟化钙的纯度;结果表明:在钙盐沉淀阶段,p H≈9,n(Ca/F)=0.75,搅拌45 min、沉降90 min;在絮凝沉淀阶段,p H≈7.5,PAC投加量为350 mg/L,最后出水氟离子浓度可降至10 mg/L以下,达到了《污水综合排放标准(GB8978-1996)》的一级标准。在钙盐沉淀阶段按照10 g/L添加大颗粒氟化钙后,氟去除率进一步提高,处理后所得的沉渣氟化钙纯度可达到85%,沉渣含水率较晶种添加前降低20%,有利于实现高效除氟和氟化钙的回收利用。     

钛石膏改性胶结材干化湖泊污泥效果及机理

通过不同养护龄期下钛石膏改性胶结材和生石灰掺量对城市湖泊污泥干化效果影响的对比研究,揭示了钛石膏改性胶结材干化污泥的效果和机理。实验结果表明,随着养护龄期增长,干化污泥含水率减少量逐渐增大;同一养护龄期,掺20%钛石膏改性胶结材的干化污泥含水率减少量明显高于掺20%生石灰的干化污泥含水率减少量;干化污泥p H趋于8时,掺20%生石灰干化污泥所用时间是掺20%钛石膏改性胶结材所用时间的7.5倍。XRD和SEM分析表明,钛石膏改性胶结材水化生成难溶的水化硅酸钙凝胶和钙矾石晶体,将大量自由水转化为结晶水;同时,水化硅酸钙凝胶、钙矾石晶体和污泥中固体颗粒之间的互相搭接和紧密结合,彻底改变了原污泥松散团聚的结构体系,将干化污泥中各相牢固地粘结成一个整体,这是钛石膏改性胶结材干化效果好的关键。     

O2/CO2气氛下醋酸钙再燃脱硝机理分析

在O2/CO2气氛下对醋酸钙再燃脱硝性能进行了试验研究,并建立由112种物质和677步基元反应组成的机理模型,对反应机理进行了探讨。试验结果表明,醋酸钙再燃脱硝效率随温度的升高呈先提高后降低的趋势,高浓度的CO2对脱硝反应有促进作用。醋酸钙分解产生丙酮,丙酮高温热解主要气体产物为CO、CH4、C2 H4、H2、C2 H2和C2 H6,这些碳氢气体能够与OH反应生成碳氢自由基和HCCO,进而与NO反应实现脱硝,高浓度的CO2对碳氢自由基的生成有促进作用。