钛精矿中氧化铝的测定——碱熔、氟盐取代络合滴定容量法

过氧化钠熔样,干过滤沉淀分离大部分钛、铁、锰等共存元素,在酸性溶液在加入过量的ＥＤ－ＴＡ,于ｐＨ５．５～６．０溶液中用氯化钠溶液回滴过量的ＥＤＴＡ,加入氟化钠置换铝—ＥＤＴＡ铬合物中的铝,定量释放出来的ＥＤＴＡ再用锌标液滴定,二甲酚澄指示剂由黄色变成红色即为终点。试验沉淀滤液中ＴｉＯ２含量的回收,研究表明;残留的ＴｉＯ２含量对氧化铝的测定影响的甚微。     

EDTA滴定总硬度实验条件探讨

ＥＤＴＡ滴定总硬度实验条件探讨匡向阳彭群英（湖南省永州水文水资源勘测局）１前言水的总硬度包含了碱金属以外的所有金属离子含量的总和。但在一般情况下,除钙、镁离子以外,其它金属浓度都很低,所以通常在ＥＤＴＡ二钠容量法测定钙、镁离子总量后,经过换算成每升水...     

用2－（2－噻唑偶氮）－5－二甲氨基苯甲酸作络合滴定铜的指示剂

用２－（２－噻唑偶氮）－５－二甲氨基苯甲酸作络合滴定铜的指示剂李秀玲，凌永萍，张瑾山东建材学院应化系济南２５００２２铜合金中Ｃｕ的测定常用方法有碘量法、ＥＤＴＡ容量法。ＥＤＴＡ容量法常用的指示剂有ＰＡＮ和二甲酚橙，但ＰＡＮ在使用过程中水溶性差、变色不...     

锆－槲皮素－EDTA三元混配络合荧光体系的研究及其应用

在弱碱性条件下，ＥＤＴＡ与Ｚｒ（Ⅳ）、槲皮素发生三元混配络合反应，形成组成比为２：１：３的锆－槲皮素－ＥＤＴＡ混配荧光络合物，由此建立了锆的选择性较好、灵敏度较高的荧光测定方法。该法测定Ｚｒ（Ⅳ）的线性范围为０．１８～３．６５μｇ／ｍｌ，方法检测限达３．５ｎｇ／ｍｌ。将此法用于直接测定合金样中的锆，结果令人满意。     

建筑石灰中CaO,MgO的测定

用镍坩埚代替银坩埚,氢氧化钠熔融分解试样。分取两份试验,一份在ｐＨ〉１３的条件下,预先加入适量氟化钾抑制硅的干扰,以三乙醇胺掩蔽铁铝。用ＣＭＰ混合指示,ＥＤＴＡ标准溶液滴定钙;另一份在ｐＨ＝１０的条件下,用酸性铬蓝Ｋ－萘酚绿Ｂ混合指示剂,ＥＤＴＡ标准溶液滴定钙镁含量,差减法求得镁的含量。     

简便快速分离测定卤水中的钙镁钡锶

本文用氢氧化钠溶液ρ（ＮａｏＨ）＝３５０ｇ／Ｌ在９０℃左右将钙镁沉淀分离后，用盐酸溶解其沉淀，以ＥＤＴＡ配位法滴定测得钙和镁的含量。滤液经盐酸酸化后，加适量硫酸将钡沉淀而与锶分离。以重量法测定钡，ＥＤＴＡ配位法测定锶。本法简便、快速，通过多批量样品实测应用，其结果均合符生产要求。     

凡口超大型铅锌矿床中方解石的某些标型特征

本文通过对凡口超大型铅锌矿床中不同类型方解石的ＲＥＥ、ＤＴＡ和热发光标型研究，发现成矿期方解石的ΣＲＥＥ总量，ＬＲＥＥ／ＨＲＥＥ比值较成岩期方解石高出２￣１０倍，矿石或矿化地层的ＤＴＡ曲线多数表现为双峰或多峰，非矿化灰岩中方解石ＤＴＡ曲线为单峰，方解石热分解温度在８１９￣８３２℃之间；矿石中的方解石人工辐射照发光多数出现１６０，２６０，３７０℃左右的三峰，而地层中的方解石多数为１６０，３７０℃的双     

锆—槲皮素—EDTA三元混配络合荧光体系的研究及其应用

在弱碱性条件下，ＥＤＴＡ与Ｚｒ（Ⅳ），槲皮素发生三元混配络合反应，形成组成比为２：１：３的锆－槲皮素－ＥＤＴＡ混配荧光络合物，由此建立了锆的选择性较好，灵敏度较高的荧光测定方法。该法测定Ｚｒ（Ⅳ）的线性范围为０．１８－３．６５μｇ／ｍｌ，方法检测限达３．５ｎｇ／ｍｌ。将此法用于直接测定合金样中的锆，结果令人满意。     

铝土矿中稀土总量的测定——PMBP-醋酸丁酯萃取偶氮胂Ⅲ光度法

矿石中微量稀土总量的分离测定一般采用离子交换法、纸上色层法、反相萃取色层法、溶剂萃取法,沉淀分离法、缓冲掩蔽法等但以溶剂萃取法较为简便快速。其中尤以PMBP—苯应用最为广泛,由于苯是有害物质,故本文研究PMBP—醋酸丁酯萃取分离微量稀土总量的体系,并对萃取分离条件,偶氮胂Ⅲ显色条件,氢氧化物共沉淀分离条件进行了探讨,制定了铝土矿中微量稀土总量的测定方法。本法测定范围RE_2O_30.02～0.2％。     

钒的交流示波极谱滴定

在有Ｂｒ＾－存在下的ＰＨ５ＨＡｃ－ＮａＡｃ缓冲溶液中，加入过量ＥＤＴＡ，用ＣｕＳｏ４标准溶液滴剩余的ＥＤＴＡ，以Ｃａ＾２＋在交流示波曲线上的切口指示终点。方法简便、准确，可用于矿石中钒的测定。     

催化电解杀菌与次氯酸钠杀菌的对比

油田回注水催化电解杀菌与次氯酸钠杀菌在杀菌机理、效果及应用成本3方面的对比结果表明,催化电解产生有效氯是主要的杀菌机理.催化电解产生的有效氯质量浓度与电解时间呈线性关系,杀菌率随着有效氯质量浓度的增大而增大.定量杀菌的对比结果表明,油田回注水催化电解杀菌比次氯酸钠杀菌效果好,且不须投加任何药剂,只消耗电能,运行成本低.     

聚合膜电解浓集法测量低水平氚环境水样的氚比活度

随着氚同位素电解浓集技术和测量仪器的发展,对低水平的氚比活度可以进行准确测量,但由于现行的氚处理方法的差异,导致氚比活度测定的不确定性增加。本文采用现行的两种氚比活度测量方法碱式电解浓集法和聚合膜电解浓集法测量低水平环境水样的氚比活度,并将结果进行比对。针对聚合膜电解法,通过使用优化结构的装置提高可靠性;对于使用国家标准方法计算出现较大误差的情况下,在氚水回收率的计算数据处理方面提出了死体积的概念,改善了聚合膜电解法测量低水平氚样品的稳定性,使氚比活度的计算结果更加精确。     

电化学循环井驱动模拟含水层化学氧化降解三氯乙烯

传统原位化学氧化地下水修复技术存在氧化剂迁移距离短和利用率低等问题。本研究在双井循环模式促进传质的基础上,通过注水井中的地下水电解原位提供O₂和H₂,配合乙二胺四乙酸(ethylenediamine tetraacetic acid,EDTA)络合溶解出含水层Fe(Ⅱ),活化O₂产生羟基自由基(•OH),实现地下水三氯乙烯(TCE)的氧化降解。在填充了砂土和黏土互层的二维砂槽中,设置电流为0.2 A、流速为72 cm/d、初始TCE浓度为3 mg/L,经过9 d的连续通电处理后,TCE浓度降低到1 mg/L,降解率达到67%。通电前投加0.5 mmol/L EDTA,经过1 d水流循环后含水层中溶解态Fe(Ⅱ)浓度从02 mg/L增加到414 mg/L,黏土区域较高。通电过程中,循环井促进O₂、Fe(Ⅱ)-EDTA和TCE的有效接触与反应,使TCE氧化降解。通电初期,黏土区域Fe(Ⅱ)氧化速率、TCE降解速率较周围慢,后期差异逐渐减小。未通电时加入醋酸钠可促进Fe(Ⅲ)还原,使含水层中铁循环利用。该修复过程通过循环井提升了氧化剂迁移距离,使用源于含水层的Fe(Ⅱ)-EDTA和稳定性较好的O₂提高了氧化剂利用率,有望应用于有机污染地下水修复。     

电解脱氮除磷技术在海产养殖废水治理中的研究

海产养殖迅速发展造成水域富营养化、赤潮频发,海产养殖废水污染的治理迫在眉睫。为解决此问题将电解脱氮除磷技术应用在海产养殖废水处理中,并探讨电压、pH、极板间距和电解时间对脱氮除磷去除率的影响。结果表明:脱氮除磷的去除率与电压成正相关,与极板间距成负相关。在电压为30V,极板间距10cm,pH为7时,NH_4~+-N、NO_3~--N和TP的去除率达到最大分别为72%、90%、85%。     

利用选择性特效树脂富集分离岩石样品中的锶钐和钕

使用目前国际上几种常用的特效树脂:锶树脂(SR)、稀土树脂(RE)和镧系树脂(LN)对岩石样品中Sr、Sm和Nd的分离富集效果进行了试验,结果表明,按厂家提供的流程,SR树脂可回收98%左右的Sr,而且残余的Rb不到2%;RE树脂回收的Sm和Nd只有70%左右;而联合利用RE和LN树脂,并配合SR树脂的使用,可以将Sm和Nd的回收率提高到90%左右;LN树脂可以很好地分离Sm和Nd,并且回收的Nd可占总样量的85%左右.     

Effect of organic complexation on the toxicity of Cu to the earthworm Eisenia fetida

The relationship between Cu speciation in solution and mortality and tissue Cu concentrations in Eisenia fetida was investigated. E. fetida were exposed to solutions containing 0.009, 0.049 and 0.125 mg Cu L⁻¹and 0, 0.15, 0.35 and 50 mg EDTA L⁻¹. Mortalities of 100, 60, 50 and 25% were recorded in the 0.125 mg Cu L⁻¹ solutions containing 0, 0.15, 0.35 and 50 mg EDTA L⁻¹, respectively. Similarly tissue body burden decreased with increasing EDTA concentration. Complexation capacity of the solution increased with EDTA concentration. In the 0.125 mg Cu L⁻¹ solution labile Cu concentration decreased with increasing EDTA concentration. These trends are attributed to complexation of free Cu ions with EDTA molecules, and the non-bioavailable nature of the resultant Cu–EDTA complex.     

Background levels and baseline values of available heavy metals in Mediterranean greenhouse soils (Spain)

This study determines extractable levels of Cd, Cu, Pb, Zn, Ni and Co in western Almería (Spain) greenhouse surface soil horizons using EDTA solution, which is identified as the fraction available for organisms and plants. It also establishes background levels, geochemical baseline concentration and reference values (RV), and investigates the possible relationships between soil properties and elemental concentrations. The results show that the soil concentration of these extractable heavy metals was high as those reported by other authors for Spanish agricultural soils. The available RV concentrations obtained (mg kg⁻¹) were: Cd 0.17, Cu 1.6, Pb 13.8, Zn 5.0 Ni 1.7 and Co 2.9. Using the upper baseline criterion, 95% of greenhouse soils present a relatively higher content of extractable heavy metals given their Cd and Cu concentration. Significant correlations between total and EDTA-extractable metal levels were found for Zn, Pb, Cu, Cd and Ni. Soil properties also related to heavy metals content, suggesting that Cd, Cu, Pb and Zn are of similar origin and relate to anthropic activities, and implies the same interactions and/or relationships among these metals.     

脉冲电解处理石油废水的实验研究

石油废水中含有多种有机物,成分复杂,其治理是当今急需解决的问题.用自制的反应器以石墨为电极材料,应用脉冲电解方法,进行处理石油废水的实验.实验结果表明:在电解时间 30 min,电解电压 10 V,脉冲电源频率 3 750 Hz,占空比 50 %,pH＝9,电极间距 2.5 cm,电极直径 1.0 cm,电解质浓度 0.2 % 的条件下进行电解,废水的处理效果可达到 89 % 以上.处理后的废水低于国家第二类污染物最高允许排放浓度的二级排放标准.脉冲电解法不但处理含油废水效果显著,而且设备简单,易于操作,为处理石油废水提供了一项新技术.     

Reclamation of EDTA by sodium tetraethylenepentamine-multi dithiocarbamate after soil washing process with EDTA

Ethylenediaminetetraaceticacid (EDTA) has been proven to be an efficient soil washing liquid to remove metal contaminants from soils. However, EDTA may cause secondary pollution due to its low biodegradability if it is not recycled or destroyed in the washing process. Thus, it is necessary to recycle and recover EDTA for sustainable use. In this paper, the extracting performance of fresh EDTA was firstly studied as a function of EDTA concentration, liquid/sediment (L/S) ratio and pH of the solution, and also extraction time. Then sodium tetraethylenepentamine-multi dithiocarbamate (TEPA-DTC), a heavy metals capturing agent, was synthesized on the base of the research of LIU-Lihua. Compared with Na₂S and DDTC, TEPA-DTC shows strong chelating capacity, because it has functional groups of dithiocarbamate that could strongly chelate heavy metals and capture metal ions from Me-EDTA to form precipitates, allowing us to reclaim the EDTA during the process of soil washing. Three divalent heavy metals were investigated (Pb, Cd, and Cu). These three metals could almost precipitate completely with TEPA-DTC under the dosage of 300 mg/l, and EDTA was regenerated. The recovered EDTA was used again in three cycles of soil washing, and the amount of heavy metals extracted just slightly decreased each cycle.     

Investigation of matrix effects in the MC-ICP-MS induced by Nb, W, and Cu: Isotopic case studies of iron and copper

Some elements normally occur at trace levels while the majority of natural geological materials may be exceedingly enriched in some special cases, such as the Bayan Obo ore deposit where REE and Nb are extremely enriched. These elements may not be removed completely during purification. Therefore, matrix effects will be caused during stable isotope ratio measurement in the MC-ICP-MS. Experiments have shown that the established methods of chromatographic separation of Cu, Fe, and Zn using AG MP-1 Anion Exchange Resin cannot make ef-fective separation of Nb, W, and Cu from Fe using 20 mL 6 M HCl. It is also observed that the elution curves of W and Cu overlap at working conditions and thus W is present in measurable amounts in some sample solutions. Matrix effects in the MC-ICP-MS induced by Nb, W, and Cu during Fe isotope ratio measurements and by W during Cu isotope ratio measurements were thus investigated by examining their changes in delta values between doped and undoped standards. The results show that the effects of the matrix elements Nb, W, or Cu on Fe isotope ratio measurements are minimal in the case of m(Nb)/m(Fe)<0.005, m(W)/m(Fe)<0.01, or m(Cu)/m(Fe)<0.6. This finding, combined with the extremely low levels of W and Cu, and the fact that nearly 90% of Nb can be removed during purification, demonstrates that the methods of chromatographic separation of Fe established before are suitable for Bayan Obo ore samples and that the methods can be simplified when Cu elution is unnecessary. The effects of the matrix element W on Cu isotope determinations are minimal in the case of m(W)/m(Cu)<0.7. Therefore, W exerts no significant effect on the measurements of Cu isotopes for the majority of natural geological materials.