新型锂吸附剂的制备研究

目前,国内外的锂离子吸附剂主要分为锰系吸附剂和钛系吸附剂两类。锰系吸附剂吸附容量不高,而且在酸洗及过滤过程中损失较大,难以实现工业化生产。钛系吸附剂具有较高的吸附容量,并且在吸附和脱附过程中内部结构保持稳定,溶损较小,具有良好的研究前景。采用二氧化钛与碳酸锂为原料,严格控制二者的配比,并在不同高温条件下发生固相合成反应,生成锂离子筛前体Li4Ti5O12。再用2 mol/L的盐酸对该锂离子筛前体进行洗脱,当此锂离子筛中的锂被完全洗脱下来后,制得了新型锂离子吸附剂H4Ti5O12。对该吸附剂作饱和吸附后,测得其饱和吸附容量QT达到32.29 mg/g。     

PAN-H_(1.6)Mn_(1.6)O_4锂离子筛膜的制备及在卤水中吸附性能

采用亲水的PAN为成膜材料,制备了掺杂H1.6Mn1.6O4的PAN-H1.6Mn1.6O4锂离子筛膜。通过SEM、Li+静态吸附实验、(NH4)2S2O8对锂的洗脱实验和卤水中吸附实验,研究了锂离子筛的添加量对PAN-H1.6Mn1.6O4锂离子筛膜结构、Li+吸附-洗脱性能的影响。结果表明,PAN浓度为10%(质量),H1.6Mn1.6O4的添加量为50%(质量)时,PAN-H1.6Mn1.6O4离子筛膜的吸附量为17.45 mg·g?1,达到粉末状吸附量的88.0%。以(NH4)2S2O8为洗脱剂,当浓度为0.3 mol·L?1、液固比为600:1、时间为12 h时,锂洗脱量为17.23 mg·g?1,锰溶损率仅为1.14%。在含有Na+、K+、Mg2+和Ca2+的罗布泊老卤卤水中,锂离子筛膜对Li+有很高的选择性。在卤水中进行10次吸附与解吸循环,吸附量从11.64 mg·g?1下降到10.94 mg·g?1,吸附容量仅损失6.0%。总体结果表明亲水性载体对H1.6Mn1.6O4吸附容量影响较小,温和的洗脱剂对锂离子筛膜的化学稳定性有利。     

硝酸锂改性钛系离子筛的制备及其吸附性能

钛系锂离子筛具有较高的锂吸附容量和稳定性,对其制备工艺及性能进行改进研究具有重要意义。使用硝酸锂和碳酸锂混合物作为锂源,与二氧化钛在500℃下进行固相反应,生成层状钛酸锂;使用0.2 mol·L~(-1)盐酸对其酸洗24 h,得到了锂离子筛吸附剂;采用X射线衍射、扫描电镜、粒度分析、N_2吸附-脱附方法等,对其性能进行了表征;通过锂离子的吸附实验,确定了吸附和再生性能;探究了该新型吸附剂的锂离子吸附机理。结果表明:吸附过程是单分子层化学吸附;经过改性,离子筛颗粒更加细小,孔体积和比表面积更大,结构完整;在70 mg·L~(-1)的Li~+溶液中,吸附量为25.01 mg·g~(-1),准二级吸附速率常数为0.2762 g·(mg·h)~(-1),吸附速率较之未改性提高了54.56%;该离子筛对浓度为11.6 mg·L~(-1)的Li+溶液,其锂去除率可以达到99.77%。     

硝酸锂改性钛系离子筛的制备及其吸附性能

钛系锂离子筛具有较高的锂吸附容量和稳定性,对其制备工艺及性能进行改进研究具有重要意义。使用硝酸锂和碳酸锂混合物作为锂源,与二氧化钛在500℃下进行固相反应,生成层状钛酸锂;使用0.2 mol·L ^-1盐酸对其酸洗24 h,得到了锂离子筛吸附剂;采用X射线衍射、扫描电镜、粒度分析、N ₂吸附-脱附方法等,对其性能进行了表征;通过锂离子的吸附实验,确定了吸附和再生性能;探究了该新型吸附剂的锂离子吸附机理。结果表明：吸附过程是单分子层化学吸附;经过改性,离子筛颗粒更加细小,孔体积和比表面积更大,结构完整;在70 mg·L ^-1的Li ⁺溶液中,吸附量为25.01 mg·g ^-1,准二级吸附速率常数为0.2762 g·(mg·h) ^-1,吸附速率较之未改性提高了54.56%;该离子筛对浓度为11.6 mg·L ^-1的Li ⁺溶液,其锂去除率可以达到99.77%。     

膨润土／活性炭复合吸附剂对土霉素的吸附性能研究

研究了一定条件下低品位钙基膨润土／活性炭复合吸附剂对土霉素废水的吸附作用。结果表明：活化温度在140℃、pH=6.5时复合吸附剂对土霉素最大吸附容量为21．78mg／g，明显大于原土的14．16mg／g，讨论并合理地解释了影响吸附的因素，适宜条件下对吸附剂多次再生，最大吸附容量仍可达到21mg／g以上。     

天然沸石吸附剂的除铅性能研究

天然佛石经活化后，对废水中的Pb(2+)有较强的吸附作用。结果表明，吸附剂504用量10g／LH2O，吸附120分钟．为适宜的反应条件。当Pb(2+)浓度为207mg／L时，吸附率可达99．5％，吸附容量为32．03mg／g且较好地符合Freundlich吸附等温式：Q＝5．56C1.84。     

锂离子筛λ-二氧化锰的固相法制备及其对锂离子的选择性

以单水氢氧化锂和四氧化三锰为原料,用固相法制备出尖晶石型锰酸锂(LiMn2O4),经硝酸洗涤脱锂后制备了锂离子筛λ-二氧化锰。测定了锂离子筛λ-二氧化锰的饱和吸附量、pH滴定曲线及分配系数,讨论了焙烧时间对前驱体锂洗脱率、锰溶损率及锂离子筛吸附性能的影响。结果表明,前驱体锰酸锂经硝酸一次酸洗后,锂洗脱率和锰溶损率分别为95%和25%;经固相法制备的锂离子筛在含0.1 mol/L氢氧化钠和10 mmol/L氯化锂的混合溶液中对锂离子的饱和吸附量为30.9 mg/g,达到理论饱和吸附量(40.2 mg/g)的76.9%;pH滴定曲线及锂离子筛对锂离子、钠离子、钾离子的分配系数均表明,该锂离子筛对锂离子具有很高的选择性。     

离子交换树脂吸附分离人凝血酶原复合物研究

用静态方法研究了扩张床用离子交换树脂Streamline DEAE对人凝血酶原复合物（以下简称PCC）的吸附性能，在此基础上初步考察了扩张床条件下的穿透吸附效果。结果表明：在静态条件下，离子强度和缓冲液浓度对平衡吸附量有着较大的影响；Streamline DEAE对PCC的吸附符合Langmuir模型，在15℃和25℃条件下其饱和吸附量分别为66．67mg／g和80．00mg／g。在扩张床条件下，Streamline DEAE对PCC的动态吸附量达36．36mg／mL；用2．0mol／L NaCl、0．01mol／L磷酸缓冲液浓度、pH=7．0的洗脱液对吸附了PCC的凝胶树脂进行洗脱，静态洗脱率达80％以上，动态洗脱曲线表明有较好的洗脱效果。Streamline DEAE对PCC的吸附洗脱性能表明，该树脂可用于扩张床吸附分离PCC的工艺。     

甲苯法生产己内酰胺水溶液的吸附精制工艺试验研究

以活性炭、活性炭纤维及离子交换树脂作为吸附剂，在甲苯法己内酰胺水溶液中试验了不同吸附剂对己内酰胺水溶液中杂质的吸附能力。结果表明，当光密度均降低30％时，采用活性炭吸附，对己内酰胺中有机杂质的动态吸附容量为26．7mL／g；活性炭纤维杂乱填充时的动态吸附容量为67．48mL／g；强碱性离子交换树脂IAR900的动态吸附容量为46．66mL／mL。提出了活性炭纤维与离子交换树脂组合吸附工艺，当光密度均降低50％时，动态吸附容量为36．67mL／g，该组合工艺能有效去除己内酰胺水溶液中的杂质，提高了产品的质量。     

海水卤水提锂高效吸附剂的合成及应用研究

高效吸附剂的研究和开发是高镁锂比海水卤水中锂分离提取的关键,当前最具工业应用前景的吸附剂为锂锰氧化物离子筛。本研究探讨了各合成条件对锂锰氧化物离子筛吸附剂的结构及吸附性能的影响,合成出了适用于不同镁锂比及锂浓度海水卤水的高容量吸附剂,吸附容量最高可达41.02 mg/g,锰溶损率为3.06%;此外,还开展了锂吸附分离的动态模拟试验,为所合成吸附剂用于海水卤水提锂的应用研究奠定基础。     

氯化钙-13X分子筛复合吸附剂的实验研究

将氯化钙填充到13X分子筛的多孔结构内钊备出了氯化钙-13X分子筛复合吸附剂,并对其吸附性能进行了实验研究。实验结果表明,复合吸附剂中氯化钙含量越高,其平衡吸附量越高,当氯化钙含量为46.2%时,其平衡吸附量最大可以达到0.557g/g,是13X分子筛的2.2倍。     

活性炭吸附法分离纯化ADN

采用静态吸附试验,研究了3种活性炭(AC、BC、CC)的静态吸附与解吸,筛选出一种较好的活性炭AC;通过动态吸附和解吸实验,对二硝酰胺铵(ADN)的吸附、解吸工艺条件进行了优化。结果表明,AC的吸附能力与解吸能力均优于活性炭BC与CC,是分离纯化ADN的理想吸附剂;当上样溶液质量浓度为30 155.32mg/L、流速为5mL/min时,活性炭AC对ADN的吸附量较大。以80℃热水为洗脱溶剂,洗脱至第10个柱体积时,总洗脱率达95.64%。     

Fast removal of ammonium nitrogen from aqueous solution using chitosan-g-poly(acrylic acid)/attapulgite composite

In this work, a novel composite adsorbent with three-dimensional cross-linked polymeric networks based on chitosan (CTS) and attapulgite (APT) was prepared via in situ copolymerization in aqueous solution, and its efficacy for removing ammonium nitrogen (NH₄⁺-N) from synthetic wastewater was investigated using batch adsorption experiments. In the adsorption test, the pH effect, adsorption kinetics, isotherms, and desorbability were examined. A comparison between as-prepared adsorbent and clay, powdered activated carbon (PAC), and other reported adsorbents was also carried out. The results indicate that as-prepared composite adsorbent is pH-dependent and has faster adsorption kinetics and higher adsorption capacity. At natural pH, the composite adsorbent with 20 wt.% APT can adsorb 21.0 mg NH₄⁺-N per gram, far higher than the other adsorbents involved. The adsorbed NH₄⁺-N can be completely desorbed by 0.1 mol/L NaOH within 10 min. All information obtained give an indication that the composite can be used as a novel type, fast-responsive and high-capacity sorbent material for NH₄⁺-N removal.     

Low cost adsorbents obtained from ash for copper removal

We investigated the utilization of ash and modified ash as a low-cost adsorbent to remove copper ions from aqueous solutions such as wastewater. Batch experiments were conducted to determine the factors affecting adsorption of copper. The influence of pH, adsorbent dose, initial Cu²⁺ concentration, type of adsorbent and contact time on the adsorption capacity of Cu²⁺ from aqueous solution by the batch adsorption technique using ash and modified ash as a low-cost adsorbent were investigated. The optimum pH required for maximum adsorption was found to be 5. The results from the sorption process showed that the maximum adsorption rate was obtained at 300 mg/L when a different dosage of fly ash was added into the solution, and it can be concluded that decreasing the initial concentration of copper ion is beneficial to the adsorption capacity of the adsorbent. With the increase of pH value, the removal rate increased. When the pH was 5, the removal rate reached the maximum of over 99%. When initial copper content was 300 mg/L and the pH value was 5, the adsorption capacity of the zeolite Z 4 sample reached 27.904 mg/g. The main removal mechanisms were assumed to be the adsorption at the surface of the fly ash together with the precipitation from the solution. The adsorption equilibrium was achieved at pH 5 between 1 and 4 hours in function of type of adsorbent. A dose of 1: 25 g/mL of adsorbent was sufficient for the optimum removal of copper ions. For all synthesized adsorbents the predominant mechanism can be described by pseudo-second order kinetics.     

Deep desulfurization of model gasoline by selective adsorption on Ag+/Al-MSU-S

The desulfurization of model gasoline containing 600 ppmw thiophene or dibenzothiophene (DBT) by selective adsorption over Ag⁺ exchanged mesoporous material Al-MSU-S was studied in a fixed adsorbent bed at ambient temperature and pressure. The results showed that the sulfur capacity increased with Al content incorporated in the silicate framework and Ag⁺ exchange can effectively improve the desulfurization performance. The best adsorbent, Ag⁺/20%Al-MSU-S, has adsorption capacity of 5 or 20 ml model gasoline containing thiophene or DBT per gram adsorbent, respectively, before the detection limit in our experiments, as a result of π-complexation. The adsorbent can be regenerated more than six times by simple calcination in air at 350 °C without obvious losing the sulfur adsorption capacity.     

Adsorption behavior of fluoride ions using a titanium hydroxide-derived adsorbent

The removal behavior of fluoride ions was examined in aqueous sodium fluoride solutions using a titanium hydroxide-derived adsorbent. The adsorbent was prepared from titanium oxysulfate (TiOSO₄·xH₂O) solution, and was characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry-differential thermal analysis, Fourier transform infrared spectrum and specific surface area. Batchwise adsorption test of prepared adsorbent was carried out in aqueous sodium fluoride solutions and real wastewater containing fluoride ion. The absorbent was the amorphous material, which had different morphology to the raw material, titanium oxysulfate, and the specific surface area of the adsorbent (96.8 m²/g) was 200 times higher than that of raw material (0.5 m²/g). Adsorption of fluoride on the adsorbent was saturated within 30 min in the solution with 200 mg/L of fluoride ions, together with increasing pH of the solution, due to ion exchange between fluoride ions in the solution and hydroxide ions in the adsorbent. Fluoride ions were adsorbed even in at a low fluoride concentration of 5 mg/L; and were selectively adsorbed in the solution containing a high concentration of chloride, nitrate and sulfate ions. The adsorbent can remove fluoride below permitted level (< 0.8 mg/L) from real wastewaters containing various substances. The maximum adsorption of fluoride on the adsorbent could be obtained in the solution at about pH 3. After fluoride adsorption, fluoride ions were easily desorbed using a high pH solution, completely regenerating for further removal process at acidic pH. The capacity for fluoride ion adsorption was almost unchanged three times after repeat adsorption and desorption. The equilibrium adsorption capacity of the adsorbent used for fluoride ion at pH 3 was measured, extrapolated using Langmuir and Freundlich isotherm models, and experimental data are found to fit Freundlich than Langmuir. The prepared adsorbent is expected to be a new inorganic ion exchanger for the removal and recovery of fluoride ions from wastewater.     

褐煤吸附MTBE(甲基叔丁基醚)的研究分析

MTBE(甲基叔丁基醚)作为一种汽油添加剂,在水环境中难降解并且不易被有机物吸附。采用颗粒状活性褐煤作为吸附剂去除水溶液中的MTBE,配制样品浓度范围为1.7μg/L~1.9 g/L。实验发现,pH值不影响吸附过程,MTBE的吸附更符合Freundlich吸附模型。在溶液起始浓度为1100 mg/L时,褐煤的最大吸附能力为21.5 mg/g。在MTBE起始浓度为74μg/L时,3 h后达到吸附平衡并且MTBE去除效率达到97.03%。由此可见,褐煤的吸附能力较高,吸附速度较快,可以作为从水溶液中去除MTBE的有效吸附剂。     

Adsorptive capacity of active filter aids for used cooking oil

Many materials are purported to adsorb polar compounds that are the result of degradation of oils used for deep-fat frying. In the present study, the capacity of several of these adsorbents in terms of the amount of polar oil degradation compounds adsorbed by a given weight of material was determined. A significant difference in the adsorptive characteristics and capacity of the materials tested was demonstrated. Adsorptive capacity varied from 0 to over 150 mg of total polar compounds per gram of adsorbent. Some of the materials demonstrated selective adsorption characteristics. For these materials, only one class of polar compounds was adsorbed.     

Adsorption behaviors of the aminated chitosan adsorbent

Using inverse suspension technology, a novel aminated chitosan adsorbent with higher adsorption ability for metal cations and metal anions was prepared. Through cross-linking amination reaction, the content of amidocyanogen of aminated chitosan adsorbent was enhanced four times than that of chitosan cross-linked adsorbent. As can be seen from the results, the adsorption ability of the novel aminated chitosan adsorbent for (Nicit)⁻ and Cr(VI) was enhanced remarkably. When the initial concentration of metallic ion was 1,000 mg/L, the adsorption capacity of the novel aminated chitosan adsorbent for nickel citrate and Cr(VI) was up to 30.2 mg/g and 28.7 mg/g, respectively. And the adsorption capacity of the novel aminated chitosan adsorbent for Ni²⁺ was still higher. So the new aminated chitosan adsorbent offers not only a higher uptake for metal cations but also a better adsorption capacity for metal anions.     

717阴离子交换树脂吸附磺基水杨酸

采用静态及动态法研究了717强碱阴离子交换树脂对水中磺基水杨酸的吸附解吸性能. 实验结果表明,在pH 2.2~12时,该树脂对磺基水杨酸有较强的吸附能力,吸附曲线符合Langmuir等温方程,吸附过程为焓驱动的放热熵减过程,吸附动力学以颗粒内扩散为主. 通过实验测得303 K时树脂静态饱和吸附容量为508 mg/g. 在315 K下用10%NaCl+2%NaOH溶液可快速洗脱树脂上吸附的磺基水杨酸,洗脱率达99%. 该树脂吸附操作简便,易再生,可望用于磺基水杨酸废水的治理及富集回收.