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。     

硝酸改性活性炭的制备及其对Cu2+的吸附性能

以不同浓度的硝酸对活性炭进行改性,用BET氮吸附法和Boehm滴定法对改性前后的活性炭进行了表征,并比较了改性和未改性活性炭对模拟含铜废水的处理效果。结果表明：经过硝酸氧化改性的活性炭比表面积有所增大,含氧官能团总量明显增加,因而对水中Cu²⁺的去除率大为提高;在常温、自然pH、活性炭用量为5 g/L、吸附时间为180 min的条件下处理浓度为10 mg/L的模拟含铜废水,经浓度为10%的硝酸改性的活性炭对Cu²⁺的去除率在70%以上,经浓度为70%的硝酸改性的活性炭对Cu²⁺的去除率接近90%;Langmuir等温吸附模型可较好地描述硝酸改性活性炭对Cu²⁺的等温吸附行为。     

碱浸改性蛇纹石尾渣吸附材料的制备及其对Cu2+的吸附性能研究

为提升蛇纹石尾渣(ALS)对重金属污染物Cu²⁺的去除效果,实现废水中Cu²⁺的高效去除,开展了蛇纹石尾渣碱浸改性研究,系统探究改性后蛇纹石尾渣吸附材料(AALS)对废水中Cu²⁺去除性能的影响。结果表明,当蛇纹石尾渣与氢氧化钠质量比为1∶0.12、改性温度为30.0℃、改性时间为90.0min时,改性效果最佳。利用BET、SEM、XRD和FTIR等分析方法考察了碱浸改性蛇纹石尾渣的改性机理。结果表明,碱浸改性致使蛇纹石尾渣的比表面积从22.62m²/g提高到67.19m²/g,碱可以侵蚀蛇纹石浸渣的结构,导致其暴露出更多Si—O—Si、Si—O官能团,增加了颗粒表面的Cu²⁺吸附位点。AALS对溶液中Cu²⁺的最佳吸附条件为AALS用量为0.15g、吸附时间为15min、溶液p H值为5.39,此时其对50.0m L浓度为125.0mg/LCu²⁺溶液中Cu²⁺的吸附量及Cu^2+...     

草酸法改性锰矿自水中吸附去除Ni2+

以草酸法改性锰矿和天然锰矿为吸附剂,研究了pH值、吸附时间、投加量对Ni²⁺吸附去除率的影响,并测定了饱和吸附量。结果表明,Ni²⁺的吸附-pH曲线呈“S”形特征,对Ni²的吸附去除率随吸附时间的延长和改性锰矿投加量的增加而提高;在25 ℃、吸附体系pH=7.0、吸附剂浓度为0.2 g/L的条件下,草酸法改性锰矿和天然锰矿对Ni²⁺的饱和吸附量分别为32.3 mg［Ni²⁺］/g和11.6 mg［Ni²⁺］/g,提高了约2.8倍。改性锰矿有望成为处理含Ni²⁺废水的新型吸附材料。     

聚酰亚胺螯合滤膜对Cu2+的吸附性能研究

通过对滤膜制备影响因素的研究, 确定了最佳制膜工艺条件, 用相转换法制备了对Cu²⁺具有较大螯合容量的螯合滤膜。研究了树脂颗粒粒径、树脂片厚度、Cu²⁺浓度、吸附温度、盐溶液pH 值和盐溶液浓度对膜吸附量的影响。对膜进行动态吸附测试表明, 聚酰亚胺鳌合滤膜(PIM D061)对Cu²⁺能实现吸附与解吸同步进行, 对Cu²⁺的最大吸附量可达800 μg/cm² 。     

钠碱脱硫液中SO2的超声波解吸

为研究低价态膜电解超声波协同钠碱再生循环烟气脱硫新工艺中SO₂气体的超声波解吸效果,探讨了超声作用时间、温度、Na⁺初始浓度、解吸液初始pH值等因素对钠碱脱硫膜电解再生溶液中SO₂解吸的影响.实验结果表明,应用超声波可提高钠碱脱硫富液中SO₂的解吸率,在短时间75 s解吸就能达到平衡状态.确定了解吸温度为95 ℃,时间为100 s,钠离子浓度为1.0 mol/L,解吸溶液初始pH=2为低频超声波解吸SO₂的适宜条件,能达到35%左右的解吸率.     

煤矸石制备沸石分子筛及其对酸性废水中Cu2+的吸附性能

煤矸石中富含SiO₂和Al₂O₃,可作为制备沸石分子筛的原料。对枣庄矿业集团煤矸石进行低温氧化、酸浸除杂和高温煅烧,再加以碱熔二次活化等预处理后,进行水热合成反应,制备了沸石分子筛。通过X射线衍射(XRD)、扫描电镜(SEM)、傅里叶红外光谱(FT-IR)对产物晶体结构、微观形貌和骨架结构进行了表征,表明产物为形态较佳且结晶度较高的4A分子筛。将所制备分子筛用于水中Cu²⁺的吸附,考察了分子筛用量、溶液pH值、吸附时间和温度对吸附效果的影响。结果表明在分子筛用量为6.0 g/L、pH值为5.0、吸附时间为180 min、吸附温度为40℃时,对Cu²⁺浓度为0.01 mol/L的酸性废水中Cu²⁺的吸附率可达89.2%。吸附动力学分析表明吸附过程符合准二级动力学方程,化学吸附在吸附过程中起主导作用。     

钠基蒙脱石对Cu2+的吸附研究

为了寻找高效、低成本、无二次污染地解决重金属离子污染问题的方法,以提纯钠化后的蒙脱石(Na-mnt)为吸附剂,在对其进行性能表征的基础上,进行了Cu²⁺吸附试验,考察了Cu²⁺初始浓度、溶液的初始pH、吸附温度及吸附时间对Cu²⁺吸附的影响,并通过Langmuir、Freundlich等温吸附模型及动力学方程从热力学与动力学角度分析了Na-mnt对Cu²⁺的吸附机理。结果表明：Na-mnt对Cu²⁺的吸附平衡数据符合Langmuir等温模型,吸附过程是一个非自发的放热反应过程,吸附过程符合拟二级动力学方程。     

二氧化硅微球对水中Cu2+的吸附行为

探索改良St9ber工艺制备的二氧化硅微球对水溶液中Cu²⁺离子吸附性能。通过X射线衍射、扫描电子显微镜、激光粒度分析、氮气吸附-脱附等分析表征了二氧化硅微球结构与性能。考查了温度、时间、Cu²⁺离子初始浓度、吸附剂投加量等因素对吸附效果的影响,探讨了吸附动力学特性与等温吸附过程。结果表明,选择0.1 g二氧化硅微球对50 mL初始浓度100 mg/L铜离子溶液在40℃条件下进行240 min吸附实验,可脱除98.49%的铜离子;伪二级动力学模型可更好地拟合吸附行为,吸附等温线符合Langmuir模型;最大理论吸附量为52.524 3 mg/g(40℃)。制备的二氧化硅微球对溶液中Cu²⁺离子具有良好吸附性能。     

新型含氧醚键吡啶萃取剂在氨溶液中的萃取与反萃性能研究

为了解决目前工业萃取剂对Cu²⁺选择性差以及对Zn²⁺萃取能力差的问题, 合成了一种新型萃取剂MPPE, 并考察了由MPPE组成的有机相在氨溶液体系中对Cu²⁺、Ni²⁺、Co²⁺和Zn²⁺的萃取与反萃性能。结果表明, 在萃取剂MPPE浓度0.06 mol/L、总铵浓度1.2 mol/L、相比(O/A)1/1、混合时间5 min、pHeq=6.44条件下, Cu²⁺萃取率达到95.8％, 而Ni²⁺、Co²⁺和Zn²⁺萃取率分别为2.8%、3.7%和8.1%, 分离系数β_Cu/Ni、β_Cu/Co和β_Cu/Zn分别高达666.20、508.42和219.55。而当其他萃取条件不变, 将平衡pH值调为8.23时, β_Zn/Ni和β_Zn/Co都达最大值, 分别为137.90和74.20。在硫酸浓度1 mol/L、反萃时间6 min以及反萃相比1/1条件下对铜和锌的负载有机相进行反萃, 锌和铜离子反萃率均在97%以上。     

红黄土对水中Cr~(3+)和Cd~(2+)的吸附性能

用天然红黄土作为吸附剂进行了去除水中Cr3+和Cd2+的试验研究,考察了pH值、吸附时间、红黄土投加量对吸附效果的影响,测定了不同pH和不同温度下的吸附等温线。结果表明:红黄土对Cr3+的吸附能力高于对Cd2+的吸附能力,一定条件下,Cr3+的去除率可达99.5%,而Cd2+的去除率最高约63%;吸附行为均符合Lang-muir单分子层吸附模型。根据试验结果,认为红黄土有望成为处理含重金属离子废水的新型吸附材料。     

The Oxidative Precipitation of Thallium at Alkaline pH for Treatment of Mining Influenced Water

Thallium (Tl) may exceed regulatory limits in mining-influenced water (MIW) associated with processing cadmium, copper, gold, lead, and zinc ores. It is a toxic metal that is soluble over a wide pH range, resulting in both persistence in the environment and poor removal by conventional lime precipitation. This study evaluated the effect of potassium permanganate (KMnO₄) at alkaline pH on Tl removal from MIW in batch experiments. The oxidation of Tl⁺ to Tl³⁺ by KMnO₄ and subsequent Tl removal was explored at Tl concentrations of ≤1 mg/L in synthetic and actual MIW. In addition to Tl, the synthetic MIW contained ≈5 mg/L of Mn, while the actual MIW contained >10 mg/L of Al, Cu, Fe, Mn, and Zn and had a pH ≈ 2.5. Dissolved Tl <2 μg/L in synthetic MIW was achieved at a pH ≈ 9 (CaO addition) and ≥5 mg/L of KMnO₄. In the actual MIW, dissolved Tl <2 μg/L was achieved at pH ≈ 9 and ≥12 mg/L of KMnO₄. The Tl removal mechanism is complicated due to the presence of reduced Mn in the synthetic MIW and multiple metals in the actual MIW. However, effective Tl removal was achieved by adding KMnO₄ to synthetic and actual MIW at alkaline pH.     

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。     

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.     

Cu2+活化黄铁矿与黄铜矿的浮选分离

在研究丁黄药体系中黄铜矿、黄铁矿单矿物的天然可浮性,石灰（调节矿浆pH）、亚硫酸氢钠、铜离子对黄铜矿、黄铁矿可浮性的影响,柠檬酸对被Cu²⁺活化的黄铁矿、黄铜矿可浮性的影响,柠檬酸-亚硫酸氢钠-石灰组合抑制剂对被Cu²⁺活化的黄铁矿、黄铜矿可浮性的影响的基础上,采用柠檬酸-亚硫酸氢钠-石灰组合抑制剂对被Cu²⁺活化的黄铁矿-黄铜矿人工混合矿进行浮选分离,得到了铜品位和铜回收率分别为24.12%和88.48%的铜精矿,及硫品位和硫回收率分别为49.69%和72.51%的硫精矿,表明该组合抑制剂对被Cu²⁺活化的黄铁矿具有良好的选择性抑制作用。     

Assessing the potential of activated bagasse as gold adsorbent for gold–thiourea

This study was conducted to establish the potential of bagasse, the fibrous by-product of sugarcane milling operation, as a precursor for preparing adsorbents for gold–thiourea complex. It was also of interest to identify the carbon properties, which promotes adsorption. Bagasse was activated in this study by physical (gasification) and chemical techniques. It was found bagasse is more amenable to activation by physical techniques producing activated carbon with surface areas exceeding 1000 m²/g. Among the chemical activating agents, it was found that ZnCl₂ was most effective in developing the surface structure of bagasse. Gold–thiourea adsorption was found to be favoured in carbon exhibiting high surface area. Finer pore sizes are developed with higher surface area. As such the extent to which the surface area could improve adsorption was limited by steric hindrance in the finer pore size. It was found that steric hindrance affected gold–thiourea adsorption in mean pore sizes less 20 Å. The effect was particularly significant when the carbon pH was greater than 7.0, where the alkaline nature of the carbon may have shifted the Tu/Au ratio to higher values such that the formation of the larger AuTu₂⁺ and AuTu₃⁺ are promoted. The greater development of physically activated bagasse favoured gold–thiourea adsorption. The optimum adsorption capacity by the physically activated bagasse was approximately 318 mg Au/g of adsorbent (ash free), achieved after 25 h of gasification in 15% CO₂. This was comparable to adsorption capacities obtained from commercial activated carbon and resins of 197–321 mg Au/g adsorbent (ash free). These results are encouraging and confirm the potential of activated bagasse as gold–thiourea adsorbent.     

Mathematical modeling of thermophilic bioleaching of chalcopyrite

Previous studies have shown that the different preferences of thermophiles to oxidize S⁰ or Fe²⁺ is reflected by different [Fe³⁺]/[Fe²⁺] levels in solution. In those studies it was concluded that [Fe³⁺]/[Fe²⁺] governs the thermophilic bioleaching of chalcopyrite rather than temperature or pH. Therefore, the proposed model is mainly based on the finding that thermophilic bioleaching of chalcopyrite is governed by [Fe³⁺]/[Fe²⁺] that result from the activity of thermophiles. A direct interaction between chalcopyrite and thermophiles is neglected because it has been reported that this is not a general behavior for all thermophiles. The case of constant temperature, initial pH 1.5–2.5, and chalcopyrite concentrates is considered. The main assumption is that chalcopyrite can be anodically oxidized or cathodically reduced depending on [Fe³⁺]/[Fe²⁺] in solution. When chalcopyrite is oxidized at high [Fe³⁺]/[Fe²⁺] levels, Cu²⁺ is formed directly at low rates: CuFeS₂ + 4Fe³⁺ → Cu²⁺ + 5Fe²⁺ + S⁰. Whereas, when chalcopyrite is reduced at low [Fe³⁺]/[Fe²⁺] levels, an intermediate (Cu₂S) is formed at higher rates: CuFeS₂ + Fe²⁺ + Cu²⁺ + 2H⁺ → Cu₂S + 2Fe³⁺ + H₂S. Because the oxidation of Cu₂S is relatively fast: Cu₂S + 4Fe³⁺ → 2Cu²⁺ + S⁰ + 4Fe²⁺, its accumulation is assumed to be negligible. To take into account the possibility of chalcopyrite being oxidized or reduced depending on [Fe³⁺]/[Fe²⁺] in solution, the principle of mixed potentials is used. The model is validated by comparing the calculated and measured values of copper extraction, total iron in solution, and pH.     

Experimental study of enhancing coalbed methane recovery by carbon dioxide injection driving methane

In order to enhance coalbed methane recovery, taking a self-developed largecale simulation system for the platform, a modeling experiment of driving CH₄ by CO₂ gas injection was studied. The results of experiment indicates that there is a significant lag effect of adsorption and desorption on gas, the gas pressure is changed more rapidly in the process of carbon dioxide adsorption of coal than methane adsorption of coal; After the injection of carbon dioxide, compare with methane single desorption. In an early stage, speed and amount of methane single desorption are greater than the speed and amount of displacement desorption, the speed and amount of displacement desorption became greater. In the process of replacement, CH₄ concentration constantly declined, while CO₂ concentration constantly rose. In the process of CO₂ gas injection, the temperature of coal have been significantly increased, it is more beneficial to make CH₄ gas molecules become free from the adsorbed state when temperature is increased. Under the pressure step-down at the same rate, using the method of CO₂ driving CH₄, compared with the method of conventional pressure step-down, the desorption rate of CH₄ in coal can be raised about 2.13 times, at the same time, a lot of greenhouse gas CO₂ will also be buried in the ground, there is a very significant environmental benefit.     

Application of ocean manganese nodules for the adsorption of potassium ions from seawater

Extracting potassium from seawater has great economic potential, although conventional methods offer low separation capacity and selectivity. In this study, a series of novel potassium ionic sieves (PISs) were synthesized using ocean manganese nodules (OMN) as raw materials. The PISs were characterized by XRD, SEM, and nitrogen adsorption–desorption. The potassium adsorption capacities and separation factors of PISs and OMN in KCl solution and sea brine showed that KMnO₄ treatment will result in the highest adsorption and separation performance. The resulted sample OMN-C exhibit major composition of birnessite-type potassium manganese oxides and high micropore volumes. The adsorption capacities of OMN-C to K⁺ in KCl solution and sea brine were 35.2 mg g⁻¹ and 22.1 mg g⁻¹, respectively. The separation factor of OMN-C was α(K⁺/Na⁺) = 108.6 and the sieve did not adsorb Mg²⁺, indicating its relatively high separation selectivity to K⁺. Therefore, OMN-C can selectively extract potassium from sea brine effectively. This study not only utilized the abundant OMN resources, but also prepared effective PISs, which showed great potential in the utilization of seawater.