凹凸棒石对Zn2+、Cu2+、Cd2+的等温吸附实验研究

凹凸棒石是一种比表面积大,吸附能力强的天然粘土矿物。为了研究凹凸棒石的吸附特征,通过等温吸附实验,进行了凹凸棒石对复合重金属离子Zn_²⁺、Cu_²⁺、Cd_²⁺的吸附容量、去除率、吸附选择性和富集系数的研究。结果表明： 凹凸棒石对Zn_²⁺、Cu_²⁺、Cd_²⁺吸附容量表现为随溶液初始浓度的增加而增加,吸附选择特征表现为对Cu_²⁺的吸附大于对Zn_²⁺和Cd_²⁺的吸附。凹凸棒石对 Cu_²⁺的去除率为96.76%,对Zn_²⁺andCd_²⁺分别为48.18%和38.84%。 富集系数与吸附特征反应的结果一致,并且吸附符合Langmuir 和Freundlich方程。研究结果表明凹凸棒石可用于水体和土壤重金属污染的修复。     

煤泥水中Ca2+在黏土矿物表面的作用

为了深刻认识煤泥水中Ca²⁺同黏土矿物颗粒之间的相互作用,笔者用Ca²⁺溶液在不同pH值条件下分别同高岭土和蒙脱土作用,测定黏土作用前后的X－射线衍射、红外光谱和X－射线光电子能谱.实验证实了在pH=5.0溶液中Ca²⁺在黏土表面以静电形式吸附;在pH=11.0溶液中Ca²⁺以Ca(OH)2沉淀和静电形式吸附;此外,在pH=8.0以上的溶液中还可能存在一羟基络合吸附形式.提出了Ca²⁺沉淀吸附和一羟基络合吸附的吸附过程模式;黏土颗粒表面的Ca(OH)₂沉淀使颗粒间形成的非选择性“静电桥”是影响沉降和浮选效果的原因之一.     

Zn2+-Mg2+-H2O系中和沉锌热力学分析及应用

湿法炼锌废电解液在冷冻结晶除镁时会生成大量ZnSO₄?7H₂O和MgSO₄?7H₂O组成的结晶产物,采用中和水解法实现结晶产物中锌、镁的分离回收。根据配位化学热力学平衡原理,绘制了298K时Zn^₂₊-Mg^₂₊-H₂O系热力学平衡图。结果表明：在pH为6.0~12.0范围内,锌离子优先沉淀析出;pH=8.0时,Zn(OH)_2(s)的条件溶度积pKs=15.6,溶液中[Zn]_T≤1.0×10^_-5mol/L。实验数据表明,在温度60℃、pH为7.0、反应时间80min的最优条件下,锌沉淀率达到100%,镁不沉淀;硫酸镁溶液经蒸发结晶得到MgSO₄?6H₂O,沉锌产物经稀硫酸浸出获得硫酸锌溶液和石膏产品。     

锡石表面铜、铅活化及黄药吸附作用的研究：DFT计算

浮选是微细粒锡石选矿中最重要的方法,其中脱硫是选锡之前的关键作业。对于脱硫过程中所引入的Cu²⁺和丁基黄药(BX),在脱硫阶段会造成锡石的损失,而在后续浮选中残余的丁基黄药会与Pb²⁺发生协同作用捕收少量锡石。本文采用密度泛函理论(DFT)研究了Pb²⁺和Cu²⁺在锡石的活化机理,以及丁基黄药在锡石表面的吸附。DFT计算结果表明,Cu²⁺、Pb²⁺均能活化锡石,且两种离子的活化机理存在显著性差异。而丁基黄药也对Cu²⁺、Pb²⁺活化后的锡石具有捕收作用,其Pb²⁺活化后的吸附能为-264.3kJ/mol,Cu²⁺活化后的吸附能为-125.5kJ/mol,Pb²⁺活化作用更强,该现象与工业现状一致。Mulliken布居显示,在Pb²⁺活化下,丁基黄药的两个S原子与Pb形成稳定螯合结构,在Cu²⁺活化下,丁基黄药的双键S2原子与Cu形成Cu-S键。     

NaCl-KCl-SmCl3熔盐体系中Sm3+在W电极上的电化学行为

钐(Sm)性能优越,使其在核电中有一定的应用,而使用熔盐电解方法制备钐合金具有实际意义。在温度750℃,使用三电极,以NaCl-KCl作为电解质,SmCl₃作为材料,运用循环伏安法,方波伏安法和计时电流法研究Sm^₃₊在NaCl-KCl-SmCl₃体系中的电化学行为。结果表明：Sm^₃₊在W电极上的电化学还原是得到1个电子的过程,其电子转移表达式为：Sm^₃₊+e^_-=Sm^₂₊,反应是准可逆反应,且没有发现其他电子转移行为;Sm^₃₊在W电极上的电化学还原是以扩散为控制步骤,且Sm^₃₊在NaCl-KCl-SmCl₃熔盐体系中的扩散系数为4.045×10^_-5cm^₂/s。     

某铀矿山废水中铀的去除试验研究

我国某铀矿山废水成分分析结果表明,废水中主要污染成分为铀,用离子交换树脂吸附处理铀,并进行了相关条件试验,条件试验内容包括离子交换树脂型号选择、树脂吸附、淋洗和合格液沉淀等条件试验。试验结果表明：用离子交换树脂处理该铀矿山废水中铀,工艺可行,处理后废水中铀浓度≤0.3mg.L_^-1,且废水中铀得到回收利用。试验用408(II)树脂进行离子交换吸附,用1M NaCl + 5 g.L_^-1 NaHCO₃作淋洗剂进行淋洗,淋洗效果好;树脂饱和吸附容量达到18 mg U.mL_^-1R,淋洗合格液中铀浓度峰值>20 g.L_^-1,贫树脂残余铀容量<0.5 mgU.mL_^-1R,沉淀回收得到的“111”产品达到国家标准。     

氧气传质对湿法炼锌过程中针铁矿法除铁的影响研究

湿法炼锌采用还原-氧化法(V.M.针铁矿法),对硫化锌精矿氧压浸出液中的铁离子进行去除,探究不同通气方式和氧气流量对除铁过程的影响。研究发现氧气的传质对氧化除铁过程有显著的影响,强化搅拌对氧气的传质影响较小,但曝气可以大大提高氧气的分散度,增加氧气传质,加快Fe_²⁺氧化速率,从而提高铁的去除效率率。研究结果表明,氧气流量≥1l/min时,氧气流量对铁的去除影响较小;在不添加晶种时,曝气氧化除铁形成大量非晶态的物质,该物质可能是铁水化合物(5Fe₂O₃.9H₂O),因吸附其他离子,阻碍沉淀物向针铁矿转变。研究结果将对湿法炼锌过程中的还原-氧化法(V.M.针铁矿法)除铁具有一定的参考价值。     

用浮选捕收剂处理电解铜废水的试验研究

电解铜废水主要含有Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 等离子,对人类健康和环境危害很大。因此,对电解铜废水进行处理方法的研究十分必要。本文研究用浮选捕集剂乙基黄药处理电解铜废水。研究结果表明：在调节该废水pH = 6.6的条件下,乙基黄药(10%)投加量20.0 mL/L,快搅时间1.5 min,慢搅时间10 min时Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 的去除率均可达到95%,处理后废水中重金属残留浓度均达到了国家污水综合排放标准(GB8978-2002)的允许排放浓度或一级标准。对重金属螯合物进行的稳定性研究指出,在pH = 9时,乙基黄药的重金属螯合物中Cu₂ 、Pb₂ 、Zn₂ 的泄漏量均为0 mg/g,Cd₂ 的泄漏量为0.8?10_-3 mg/g,Ni₂ 的泄漏量为14.2?10_-3 mg/g,处理后的污泥稳定性好,对环境无二次污染。浮选捕收剂乙基黄药具有pH应用范围广、操作简单、处理成本低、效果稳定等优点,在重金属废水治理中具有良好的应用前景。     

基于无定形砷酸铁沉淀的铜冶炼污酸除砷研究

针对传统石灰?铁盐污酸处理工艺产出的中和渣含砷高、不能进入柔性填埋场堆存的现状,采用基于无定形砷酸铁沉淀的预中和?铁盐沉砷方法,降低石灰?铁盐污酸处理流程中和渣砷含量,确保含砷渣能够进入柔性填埋场。热力学分析发现,砷酸铁稳定存在的pH值为0～5.2;在pH＝4～5时,As-Fe-H₂O体系中砷酸铁可以形成并稳定存在,同时不会产生Fe(OH)₃沉淀。研究表明,石灰乳预中和过程终点pH为4.5时,没有砷酸钙沉淀产生或少量产生,预中和石膏含砷小于3%。铁盐沉砷过程温度和初始pH值的升高,有利于降低沉砷后液As浓度、增加As沉淀率和沉砷渣中As含量;但提高初始铁砷摩尔比和初始砷浓度,并不利于砷的沉淀。在低温(40oC)及较短的时间(1h)的条件下,单独采用空气或者80%氧气作氧化剂,难以获得较好的沉砷效果,必须加入适量的H₂O₂,以提高As₃₊^{离子的氧化效率。在优化条件下,沉}砷后液平均砷浓度为2.80g/L,沉砷渣平均含砷27.01%,沉砷渣为疏松多孔的无定形砷酸铁,砷沉淀率为71.62%。沉淀反应是无定形砷酸铁生成过程的限制步骤。     

棉花坑矿床细粒花岗岩黑云母微区地球化学特征及其地质意义

对粤北棉花坑铀矿床细粒黑云母花岗岩中的黑云母进行了系统的矿物化学分析,旨在探讨黑云母对成岩成矿作用的指示意义。电子探针(EMPA)测试结果显示,细粒花岗岩中黑云母富FeO_T、TiO₂,贫MgO、Al₂O₃,属铁叶云母。Fe^₂₊/(Mg+Fe^₂₊)比值介于0.89~0.93,TiO₂/MnO比值介于2.89~4.59,并显示贫钙的特征,为典型的岩浆成因黑云母;其F含量较高(平均为0.69%),表明岩浆熔体富F。激光剥蚀电感耦合等离子质谱(LA-ICP-MS)原位微量分析表明黑云母稀土总量较低,∑REE含量为13.85×10^_-6~25.18×10^_-6。轻重稀土比值LREE/HREE为1.04~1.69,显示出轻重稀土分馏不明显。球粒陨石标准化的稀土元素配分模式呈典型的平缓“V”字形,且具明显的Eu(δEu为0.016~0.021)负异常。在原始地幔标准化蛛网图中,黑云母相对全岩富集Rb、Ta、Nb、Sc、V、Co,而相对亏损Th、U、Sr、Zr等元素。估算得出黑云母结晶温度为437~502℃,氧逸度lgf (O₂)为10^_－18.7~10^_－20.8,表明其形成于低温、低氧逸度条件。上述特征指示寄主岩石为壳源成因的高分异S型花岗岩,与产铀岩体具相似特征,低温、低氧逸度和高挥发分氟含量等条件有利促使铀元素富集。     

碳酸盐矿化菌诱导碳酸钙沉淀条件的优化

通过单因素及正交试验研究了温度、pH值、沉淀时间、反应物浓度和成核剂5个因素对微生物诱导CaCO3沉淀量的影响,以期提高微生物沉积碳酸钙的产率,为微生物修复技术的时效性提供参考。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、热分析仪(TG)、能谱分析(EDS)对CaCO3样品形貌、结构、热性质、元素等进行表征分析。结果表明,沉淀物质主要含有C、O、Ca元素和少量有机质,其晶型、形貌和堆积密度随外界条件改变而不同。微生物诱导CaCO3沉淀的最佳外界条件是:pH值为8,Mg2+浓度0.05mol/L,温度40℃,沉淀时间3 d,Ca2+浓度1.5mol/L。     

Barium Carbonate Process for Sulphate and Metal Removal from Mine Water

Abstract.  The removal of sulphate and metals from mine water was assessed using the integrated barium carbonate process and the co-precipitation of barium sulphate with calcium carbonate. The rate of sulphate removal was influenced by the BaCO₃ concentration and the cation associated with sulphate, and increased with increasing BaCO₃-concentration. BaCO₃ can only be used for removal of sulphate that is associated with calcium, as calcium is needed to remove the added carbonate associated with the barium cation. Sulphate removal was only marginally influenced by alkalinity. Sulphide can be stripped with CO₂ from a BaS-solution. The (CO₂ dosed/sulphide removed) molar ratio was close to unity for the first 50% of sulphide in solution. The stripped H₂S-gas can be absorbed into zinc acetate. BaSO₄ and CaCO₃ can be converted simultaneously to BaS and CaO, respectively at an optimum temperature of 1050°C. The CaCO₃/BaSO₄ molar ratio has little influence on the yield of BaS. The running cost of the barium carbonate process for the removal of 2 g/L of sulphate totalled ZAR1.28/m³ (US$1.00 = ZAR7.0, Feb 2007), the capital redemption cost was R1.08/m³, and the value of the products (water and sulphur) totalled R2.76/m³.     

膨润土吸附水中Zn2+的影响因素研究

研究了邯郸钙基膨润土及其钠化土对Zn²⁺的吸附行为,考察了溶液中Zn²⁺的初始浓度、液固比、pH值、吸附时间、搅拌速度、温度、膨润土粒度等因素对膨润土吸附的影响。结果表明：钙基膨润土及其钠化土对Zn²⁺的吸附在2 h时都基本达到平衡;提高溶液的pH值、吸附温度和搅拌速度,延长吸附时间,降低膨润土的粒度、Zn²⁺的初始浓度和液固比,都能不同程度地提高膨润土对Zn²⁺的吸附率;在混合体系中,共存离子Pb²⁺对两种膨润土吸附Zn²⁺的效果都几乎没有影响,而Cr⁶⁺却会降低?街峙蛉笸炼訸n2+的吸附率。     

Attenuation of heavy metal ions by lean grade phosphorite

The sorption of heavy metal ions (Pb²⁺, Cu²⁺ and Zn²⁺) present as a single and as well as multiple species onto a low grade (<15%P₂0₅) carbonatic (CA) and siliceous (SL) phosphorite minerals from Madhya Pradesh (India) was investigated under natural conditions. Sorption of heavy metal ions was found to follow the order: Pb2+ >Cu²⁺ > Zn2+ in the cases of single and multiple species. CA was found effective in removing Pb²⁺, with a Pb removal of 82 – 99.9 % and a maximum L.R.C (lead removal capacity) of 0.082 g of Pb / g of carbonatic phosphorite.     

Impact of lead/zinc ore mining on groundwater quality in Trzebionka mine (southern Poland)

The intensive mining activity carried out by “Trzebionka” zinc-lead mine causes changes in the hydrodynamic regime of the triassic aquifer as well as essential changes in the chemical composition of the groundwater. The mine water, in comparison with groundwaters collected directly from fractures and Karstic channels and with groundwaters pumped out from wells situated in Chrzanow region, is characterized by higher contents of almost all major dissolved constituents as, well as, many trace elements. Hydrogeochemical background of triassic carbonate series aquifer has been elaborated. Largest anomalies in extent of almost all elements have occurred in area of the “Trzebionka” mine. In this water general trend of increase of pH, total dissolved solids and SO₄ ²⁻ concentration with simultaneous trends of decrease of Zn²⁺ and Pb²⁺ concentrations have been noticed. Water pumped out from the mine in spite of its low quality, is utilized in about 80% as potable water after undergoing complicated treatment.     

Adsorbing colloidal flotation removing metals ions in a modified jet cell

The removal of Cu²⁺, Zn²⁺ and Ni²⁺ ions from synthetic wastewater with a modified Jameson cell (MJC) was studied using adsorption colloidal flotation (ACF). A colloidal dispersion of Fe (OH)₃ (formed in situ from FeCl₃) at pH 11 was used as an adsorbent colloid to ensure full adsorption and precipitation. The precipitates were flocculated with polyacrylamide and hydrophobised with sodium oleate and pine oil as a frother during the flotation stage. In the modified jet cell, the downcomer was sealed at the bottom with a diffuser, and the re-flotation of detached flocs and the probability of bubbles/particles capture was enhanced, which improved the recovery rate. As a result, the modified Jameson cell was more efficient (higher loaded carrier recoveries) than the conventional jet cell (CJC) in removing heavy metals ions. The physico-chemical characteristics, cell design and operating parameters were studied, and the removal efficiency was evaluated by monitoring the final concentration of ions in the treated effluent. The results indicated that the removal efficiencies of the MJC were approximately 95% and 98% for dilute (Cu²⁺, Zn²⁺ and Ni²⁺ concentration of 2 mg/L) and concentrated wastewater (25 mg/L of each ion), respectively. The optimal parameters included a Fe⁺³/ion ratio of 0.5 and a minimum air flow-rate/feed flow-rate ratio of 0.18. The results are discussed in terms of the physical and physico-chemical parameters, and the findings suggested that the proposed flotation technique has great potential for the treatment of wastewater.     

天然及改性膨润土吸附废水中Pb2+、Ni2+、Cd2+ 的试验研究

用山东潍坊涌泉某膨润土厂生产的天然钙基膨润土和改性膨润土对模拟含Pb²⁺、Ni²⁺、Cd²⁺的废水分别进行了试验研究。结果表明,该厂的天然钙基膨润土和改性膨润土对废水中的Pb²⁺、Ni²⁺、Cd²⁺有较高的去除率,可以作为重金属离子Pb²⁺、Ni²⁺、Cd²⁺的吸附剂使用     

淀粉衍生物DSX的合成及对重金属的吸附

将以氮为中心的交联淀粉与丙烯酰胺进行接枝共聚和磺化,合成了淀粉衍生物硫代氨基淀粉黄原酸盐（DSX）,并通过红外光谱分析对其结构进行了表征。用DSX处理Cu²⁺,Pb²⁺,Zn²⁺,Cd²⁺浓度均为20 mg/L的模拟重金属废水,结果表明,当温度为20 ℃,pH为7,DSX投加量为1.5 g/L,处理时间20 min时,Cu²⁺,Pb²⁺,Zn²⁺, Cd²⁺的吸附去除率分别达到99.5%,99.4%,99.0%,99.2%。     

用高锰酸钾改性提高竹炭对Cu2+ 的吸附能力

采用KMnO₄溶液在回流状态下对竹炭进行改性,得到改性竹炭。比较研究了 KMnO₄浓度对Cu²⁺ 在竹炭上的吸附率-pH曲线的影响,并研究了KMnO₄改性对竹炭吸附和解吸Cu²⁺ 性能的影响。静态吸附试验表明, KMnO₄ 改性使竹炭对Cu²⁺ 吸附率-pH曲线及pH₅₀向低pH偏移,当 KMnO₄溶液浓度为0.04 mol/L时,改性效果最好; KMnO₄ 改性使其投加量节省约2倍; 竹炭对Cu²⁺ 的吸附均遵循Langmuir单分子层吸附规律, 在相同Cu²⁺ 平衡浓度下,改性后的竹炭对Cu²⁺ 的吸附量提高约53%,升高温度能明显提高改性竹炭对Cu²⁺ 的吸附能力,40 ℃的饱和吸附量是25 ℃的1.69倍。KMnO₄ 改性提高了竹炭从水中吸附重金属离子的能力,并改善了其解吸再生性能。     

Using Calcium Carbonate/Hydroxide and Barium Carbonate to Remove Sulphate from Mine Water

This study evaluated the effectiveness of using barium bicarbonate to remove sulphate from neutralized AMD. The Ba(HCO₃)₂ was produced by dosing a BaCO₃ solution with CO₂ to form Ba(HCO₃)₂. This greatly increased the barium ion concentration, which rapidly removed sulphate linked to either calcium or magnesium. Following sulphate removal, the Ca(HCO₃)₂ or Mg(HCO₃)₂ containing water can be stabilised by CO₂ stripping with air, which results in CaCO₃ precipitation. The MgCO₃ remains in solution.