一个与吸附剂浓度有关的Langmuir等温式

实验测定了不同吸附剂浓度下, 高岭土对Pb(II)和Cu(II)的吸附作用, 结果表明存在明显的吸附剂浓度效应, 即吸附等温线随吸附剂浓度升高而降低. 采用传统的Langmuir 吸附等温式对实验数据进行拟合表明, 此等温式可准确地描述给定吸附剂浓度下的吸附结果, 但不能预测其吸附剂浓度效应. 根据表面组分活度(SCA)模型, 假设吸附剂颗粒间存在相互作用, 吸附剂表面吸附位的活度系数不等于1, 而应为吸附剂浓度的函数, 推导出了一个与吸附剂浓度有关的Langmuir (Langmuir-SCA)方程. 运用高岭土吸附Pb(II)和Cu(II)以及文献中蛭石吸附Zn(II)和Cd(II)、咖啡吸附Pb(II)的实验数据检验方程的适用性, 结果表明Langmuir-SCA方程可准确地描述所观察到的吸附剂浓度效应. 方程的两个内禀参数, 热力学平衡常数(K_eq)和特征饱和吸附量(Γ_m⁰), 与吸附剂浓度无关, 并可由吸附实验数据拟合求得.     

由表面活性物质溶液的动界面张力外推求平衡界面张力的研究

表面活性物质溶液的界面张力往往随时间而变,难以测得平衡界面张力J。Kloubek^[1]曾应用经验式:1/(δ_H2O-δ_t)=b/(At^1/2)+1/A,以[1/(δ_H2O-δ_t)]对1/t^1/2作图外推求得溶液的平衡表面张力,但所得结果仅与文献值大致相符。本文从理论上分析该经验式的由来,以及产生偏离的原因,并寻求了解决的办法。     

氧化反应对胜利褐煤水蒸气气化反应的促进作用Ⅰ:宏观反应特性研究

在φ80×3 000mm耐高温不锈钢管气流床反应器中,以150-180μm胜利褐煤为气化原料,考察了800和900℃时添加氧气前后褐煤转化率的变化,研究了氧化反应对水蒸气气化反应影响的宏观特征。结果表明,添加氧气后褐煤转化率明显大于O_2和H_2O气氛下褐煤转化率之和,即向水蒸气气氛添加氧气后褐煤转化率的增幅大于氧气氧化作用导致的褐煤转化率的增幅,随着H_2O含量增大以及温度的升高此现象愈加明显。该协同作用主要是氧化反应对水蒸气气化反应的促进作用造成的。利用φ40×200 mm石英圆筒流化床反应器进行了类似的实验,也发现了该协同作用。同时,借鉴收缩核模型并结合气流床气化实验条件推导了水蒸气气化宏观动力学方程,得到的速率方程(Z-(1-x))~(1/3)=(tβk_(H_2O)/Rρ_C)φ_(H_2O)=K_(H_2Oφ_(H_2O))与实验值吻合较好,添加氧气后水蒸气气化反应速率和水蒸气气化反应表观速率常数K_(H_2O)明显增大,这是氧气对水蒸气气化反应促进作用的动力学特征。     

O2/CO2气氛下污泥/煤混燃中半挥发性重金属的释放特性

在固定床焚烧实验装置上,采用正交实验法研究了焚烧温度(t_c)、污泥掺混比(X_s)、O_2体积分数(φ_(O2))、初始含水率(φ_(H2O))、焚烧时间(τ)和含氯量(φ_(Cl))六个因素对O_2/CO_2气氛下污泥/煤混燃中半挥发性重金属(Zn、Pb、Cd、Cu、Ni和Cr)释放特性的影响。结果表明,六种因素对重金属释放率影响程度排序为t_cX_sφ_(H2O)φ_(O2)≈τφ_(Cl)。相同焚烧工况下,Zn释放率最大,Pb和Cd次之,Cu、Ni和Cr较小。提高温度会促进重金属释放,且高温(1000-1100℃)对重金属释放的影响显著强于低温(700-900℃)。随着温度由700℃升高至1100℃,Zn和Pb释放率分别由36.1%和12.2%上升至70.9%和63.5%,Cd在900℃下达到40.0%的最大释放率,而Cu、Ni和Cr释放率大都维持在20.0%以下,温度对重金属释放率影响程度排序为PbZnCdCuCrNi。重金属释放率随着污泥掺混比增加逐渐下降,却随着初始含水率增加呈现波浪式变化趋势,且在30%O_2体积分数下重金属释放率取得最小值。焚烧时间和含氯量对Pb释放的影响程度显著强于其他五种重金属。O_2/CO_2气氛下污泥/煤混燃的最佳工况为:焚烧温度为900-1000℃、污泥掺混比为25%左右、O_2体积分数为30%、初始含水率小于10%,并尽可能的缩短焚烧时间。     

Adsorption of anionic dye by anionic surfactant modified chitosan beads: Influence of hydrophobic tail and ionic head-group

In this paper, how chitosan hydrogel beads were modified by anionic surfactants (SDS, SDOS, SDBS, AOT, and DTM-12) and then used for the adsorption and removal of an anionic dye (congo red) from aqueous solutions were described. The effect of surfactant concentration, surfactant ionic head-group, and surfactant hydrophobic tail were investigated in detail. The result revealed the modified CS beads all had the obviously higher adsorption capacity than CS beads. Compared to the ionic head-group, the hydrophobic tail of the surfactant plays more important role in the adsorption, and a high adsorption capacity was observed for CS/AOT beads and CS/DTM-12 beads (both with two hydrophobic tails). The Sips isotherm model showed a good fit with the equilibrium experimental data, and the values of the heterogeneity factor (n) indicated heterogeneous adsorption. The adsorption kinetics analysis indicated that the pseudo-second-order rate model could better describe the adsorption process than the pseudo-first-order rate model.     

钽掺杂六方相氧化钨对Sr2+的吸附:Zeta电位的测量及吸附机理的研究

研究Ta掺杂六方相氧化钨(hex-WO₃)材料在吸附Sr²⁺过程中其表面zeta电位的变化情况,并进一步探讨了吸附过程的热力学及吸附机理。结果表明：(1)在实验pH值范围内,Ta掺杂hex-WO₃悬浮液的zeta电位值随溶液中电解质的价态增大而增大;(2)且zeta电位随体系中离子强度的增加而增大;(3) Ta掺杂hex-WO₃对Sr²⁺的吸附容量随着温度降低而增大,随着离子强度的增加而减少;(4)吸附过程的吸附焓为－47 kJ·mol^-1,且Sr²⁺离子与材料表面之间主要为化学相互作用;(5) Ta掺杂hex-WO₃对Sr²⁺吸附过程主要为材料表面吸附及材料孔道内离子交换共同作用。     

介孔TiO2对溶菌酶吸附的动力学和热力学

773.15 K下焙烧二钛酸(H₂Ti₂0₅)制备了介孔结构TiO₂。采用比表面分析仪(BET)、扫描电镜(SEM)、拉曼(Raman)光谱和X射线衍射(XRD)仪进行表征研究了介孔TiO₂对溶菌酶的吸附行为和机理。结果表明,该吸附过程较好地满足Langmuir吸附模型;随着溶液pH值的增高,溶菌酶在介孔TiO₂上的吸附量先增大后减小。在pH = 7.2时,达到最大吸附容量72.5 mg·g^-1。该介孔TiO₂对溶菌酶具有良好的吸附稳定性,经过5次循环后吸附的溶菌酶残余量仍有81.6%。动力学研究表明,介孔TiO₂与溶菌酶间的吸附满足准二级动力学模型,吸附传质过程由膜扩散和粒内扩散共同影响与控制。对热力学参数的计算发现,该过程ΔG⁰ < 0, ΔH⁰ > 0, ΔS⁰ > 0,表明介孔TiO₂对溶菌酶的吸附是一个自发的、吸热的熵增过程。     

二氧化碳/甲烷/氮气二元混合物在有序介孔碳材料CMK-3 中的吸附和分离

采用分子模拟与吸附理论研究了天然气成分在有序介孔碳材料CMK-3上的吸附和分离.巨正则系综蒙特卡罗(GCMC)模拟表明,CH4和CO2气体的较优存储条件分别为208 K、4 MPa和298 K、6 MPa,其最大超额吸附量分别为10.07和14.85 mmol· g-1.基于双位Langmuir-Freundlich (DSLF)模型,使用理想吸附溶液理论(IAST)预测了不同二元混合物在CMK-3中的分离行为,发现吸附选择性Sco2/CH4与ScH4/N2比较接近,在298 K和4 MPa下约等于3,而N2-CO2体系中的CO2吸附选择性较高,可达到7.5,说明CMK-3是一种适合吸附和分离天然气组分的碳材料.     

核桃青皮制备高含氧量多孔炭及其对Ni2+的吸附性能

以核桃青皮为原料, 先用水热法制备其炭前驱体, 然后以不同的温度活化得到生物质炭(HBC_x). 采用扫描电子显微镜(SEM)、 傅里叶变换红外光谱(FTIR)、 氮气吸附-脱附仪(BET)和X射线光电子能谱(XPS)等手段对HBC_x进行了表征, 并考察其对废水中高浓度和低浓度Ni²⁺的吸附性能. SEM和BET表征结果表明, 大量的大孔(约2 μm)均匀地分布在HBC_x上, 其具有分级多孔结构, 当活化温度为800 ℃, 所得HBC₈₀₀的比表面积为 94 m²/g, 平均孔径为4.07 nm; 炭材料表面含氧和含氮官能团丰富, 氧含量(摩尔分数)高达21.24%, 可与Ni²⁺发生离子交换或共沉淀, 这些基团有利于吸附过程的进行. 所制备的多孔炭对废液中低浓度的Ni²⁺去除率接近100%, 表现出优异的吸附性能. Langmuir等温模型能很好地描述了HBC_x对Ni²⁺的吸附过程, 为单分子层吸附, HBC₈₀₀对Ni²⁺的最大理论吸附量高达127.39 mg/g. 拟二级吸附动力学模型可以更好地反映吸附过程, 吸附速率主要由化学吸附所控制. 固定床动态吸附结果表明该材料有优异的工业应用前景.     

Time-resolved vibrational cemiluminescence: Rate constants for the reaction F + HC1 → HF + Cl and for the relaxtion of HF(v = 3) by HCl, CO2, N2O, CO, N2 and O2

The reaction: F + HCl→ HF (v 3) + Cl (1), has been initiated by photolysing F₂ using the fourth-harmonic output at 266 nm from a repetitively pulsed Nd: YAG laser By analysing the time-dependence of the HF(3,0) vibrational chemiluminescence, rate constants have been determined at (296 ± 5) K for reaction (1), k₁ = (7.0 ± 0.5) × 10⁻¹² cm³ molecule⁻¹ s⁻¹, and for the relaxation of HF(v = 3) by HCl, CO₂, N₂O, CO, N₂ and O₂: k_HCl = (1.18 ±0.14) × 10⁻¹¹ k_CO2 = (1.04 ± 0. 13) × 10⁻¹², k_N2O = (1.41 ± 0.13) × 10⁻¹¹ k_CO = (2.9 ± 0.3) × (10⁻¹², k_N2 = (7.1 ± 0.6) × 10⁻¹⁴ and k_O2 = (1.9 ± 0.6) × 10⁻¹⁴ cm³molecule⁻¹s⁻¹.     

Adsorption of polyacrylic acid on aluminium oxide: DRIFT spectroscopy and ab initio calculations

Diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy was used to study the adsorption process of the water-soluble polyacrylic acid (PAA) polymer on hydrous δ-Al₂O₃. Vibrational assignment of PAA, sodium polyacrylate, (Na–PA) and the PA-oxide surface complex was achieved by comparison of observed band position and intensity in the DRIFT spectra with wavenumbers and intensities from ab initio quantum mechanical calculations. The presented data of polyacrylic acid suggest that IR data calculated ab initio on relatively short oligomers (quantum-mechanical oligomer approach) may provide valuable information regarding the interpretation of polyelectrolyte infrared spectra. Batch adsorption experiments were performed to sorb PAA onto the δ-Al₂O₃ surface. The results obtained from DRIFT studies were compared with adsorption isotherm experiments in order to relate the level of PAA coverage to the nature of the surface complex. Ab initio molecular orbital calculations on PAA/Al₂O₃ clusters were used to model possible surface complexes. Strong correlation were found between theoretical and observed DRIFT frequencies of the antisymmetric R-COO⁻ vibration. A number of possible configurations of the polyacrylic acid/aluminate surface complex were tested via ab initio calculations. These possible configurations included different di-aluminium octahedral Al³⁺ surface models. Results obtained from adsorption isotherm experiments, DRIFT spectra and ab initio calculations indicate that the carboxylate oxygens bridge an Al³⁺-octahedral dimer [Al₂(OH)₂4(H₂O)2(OH)] in a ligand-exchange inner sphere complex.     

大孔吸附树脂对肿瘤坏死因子吸附性能的研究

选用NK-110、碳化树脂和MET-10043种大孔吸附树脂,通过对树脂吸附量的测定,吸附动力学曲线和吸附等温线的描述等方法,研究了3种大孔吸附树脂对血浆中TNFα的吸附性能,结果表明NK-110和MET-1004对TNFα的吸附量较高,其中又以MET-1004的吸附速率最快     

Preparation of MnO2 Loaded Hydrothermal Carbon-coated Electrospun PAN Fiber Membranes for Highly Efficient Adsorption and Separation of Cationic Dye

Hydrothermal carbonaceous materials and MnO₂ have been proved to be promising adsorbents to remove organic dyes from wastewater. In this study, flexible MnO₂ loaded hydrothermal carbon-coated electrospun poly-acrylonitrile(AC/MnO₂/PAN) fiber membranes were fabricated by a facile one-step hydrothermal method and activated by NaOH solution. The composite fibers exhibited large adsorption capacity toward cationic dyes and excellent mechanical properties. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption for methylene blue(MB), methyl violet(MV) and malachite green(MG) are 1173.27,1106.31 and 1129.89 mg/g, respectively, according to Langmuir fitting. The AC/MnO₂/PAN fiber membrane also showed satisfactory performances for selective adsorption and recyclability. In addition, based on selective adsorption, the AC/MnO₂/PAN fiber membranes that are repulsive to the anionic dye methyl orange(MO) can separate the MB/MO mixture solution by dynamic filtration. Thus, this work not only provides a facile strategy to fabricate large capacity adsorbents, but also demonstrates the potential applications in the dye wastewater treatment field.     

Efficiency of Cd(II) removal from aqueous media using chemically modified polystyrene foam

The removal of Cd(II) using polystyrene foam chemically modified with 2,2′-bipyridine has been investigated. The modified polystyrene foam has been characterized by FT-IR spectroscopy, thermogravimetry, elemental analysis and scanning electron microscopy. The solid was employed as a Cd(II) adsorption from aqueous solutions at room temperature. The effects of several variables (pH, shaking speed, agitation time, metal concentration and presence of other ions in the medium) have been studied using batch technique. Flame atomic absorption spectrometry was used to determine the Cd(II) ion concentration in the filtrate after the adsorption process. Maximum sorption 90% was achieved at pH 7 after 30 min of shaking time. Sorbed metal ions have been desorbed with 5 ml of 2 M HNO₃ with the detection limit of 16.7 ng ml⁻¹. The Langmuir, Freundlich and D–R isotherm equation were used to describe partitioning behavior of the system at room temperature. Kinetic and thermodynamic behavior of modified polystyrene foam for Cd(II) ion removal was also studied. Br⁻, PO₄³⁻, Pb²⁺, Ni²⁺ and Cr(VI) suppress the sorption to some extent. The possible sorption mechanism of Cd(II) ions onto modified sorbent is also discussed. Method was utilized to remove Cd(II) ions from aqueous media.     

NO与NO2在ZnO表面吸附的密度泛函理论研究

采用 DMol ³ 模块中广义梯度密度泛函理论(GGA)的Perdew-Burke-Ernzerh(PBE)方法研究含能材料分解气体产物NO, NO₂在ZnO(10 \bar{1} 0)表面的吸附和NO₂解离生成NO和O的过程. 结果表明, 优化后的吸附构型显示Zn顶位为稳定吸附位点, NO₂的吸附能大于NO. 态密度图分析结合差分电荷密度图表明, NO的N原子与表面Zn有相互作用, 电荷从NO转移到表面; NO₂的N_2p, O_2p轨道与表面Zn_3d轨道发生杂化, NO₂附近积累大量负电荷. 过渡态搜索显示NO₂的解离需跨过较高能垒, 不易进行.     

纯相钙铝层状双氢氧化物对磷的吸附特性

采用乙醇辅助液相共沉淀法制备了纯相Ca-Al-LDH层状双金属氢氧化物,考察了Ca-Al-LDH的投加量、吸附时间、pH值、无机电解质(Na₂CO₃ ,KCl ,Na₂SO₄,KNO₃)和温度等因素对磷吸附的影响,结果表明,纯相Ca-Al-LDH对磷酸根离子具有很好的吸附性能,最大饱和吸附量可达160.78 mg/g,当pH值为5.1、温度为45 ℃、吸附时间为600 min、LDH投加量为0.6 g/L、磷初始浓度为80 mg/L时,磷的去除率高达95.88%;无机阴离子会抑制磷在吸附剂上的吸附,当Cl^-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量从69.96 mg/g降至53.18 mg/g,降低了23.99%;当SO₄^2-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量降低了24.79%,其它无机阴离子对磷在吸附剂上的吸附也有一定的影响。 Ca-Al-LDH对水中磷的吸附符合二级动力学方程和Langmuir等温模型。 采用扫描电子显微镜、傅里叶变换红外光谱仪和X射线衍射仪等技术手段对制备的纯相Ca-Al-LDH及其吸附磷酸根后的产物进行表征,揭示了Ca-Al-LDH对磷酸根的吸附可能是静电吸引、化学吸附和阴离子插层等过程协同作用的吸附机理。     

High-throughput model-building and screening of zeolitic imidazolate frameworks for CO2 capture from flue gas

To find potential zeolitic imidazolate frameworks(ZIFs)for CO2 capture from flue gas,we built 169,898 ZIF models from 84,949 hypothetical zeolite networks.By calculating their lattice energies,accessible volumes to CO2,the isosteric adsorption heat(Qst)of H2 O,Henry’s constant ratio(SKH)of CO2/N2,percent regenerability(R%),CO2 working capacity(ΔNCO2),CO2/N2 adsorption selectivity(SCO2/N2))and adsorbent performance score(APS),we identi fied 49 hydrophobic ZIF structures that might outplay already-realised ZIFs built from the same imidazolate linkers for CO2 capture from flue gas.     

Adsorption of CO2 and H2 on Nitrogen-doped Porous Carbon from Ionic Liquid Precursor

Nitrogen-doped mesoporous carbon material was prepared via a simple one-step thermolysis method via the carbonization of ionic liquid, 1-cyanomethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([MCNIm]⁺[Nf₂T]^-). The nanostructure of the resultant carbon material was characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM) and the types of N-containing groups of the carbon material were investigated by X-ray photoelectron spectroscopy(XPS). The N-content of the carbon material is 18.6%(mass fraction) based on the elemental analysis. The produced mesoporous carbon material was further used as the solid sorbent for H₂ and CO₂. The hydrogen uptake capacity and H₂ isosteric heat of the carbon material were discussed. Furthermore, the nitrogen-containing carbon material as good sorbent shows relatively high adsorption and separation ability for CO₂ from CH₄, for which the heat of CO₂ adsorption(Q_st) is 31.8 kJ/mol. The mesoporous structure and nitrogen functionality make the carbon material with high adsorption capacity and selectivity for CO₂ and ability to store H₂, indicating that this kind of nitrogen-doped carbon material originated from ionic liquids is a promising sorbent material for high-performance separation and adsorption.     

立方体纳米Cu2O吸附热力学及动力学的粒度效应研究

采用不同粒径的单一(100)晶面的立方体纳米Cu₂O作为模型材料, 研究了粒径和温度对其吸附动力学和吸附热力学性质的影响规律. 基于已建立的纳米材料吸附热力学和动力学理论, 推导出了单一(100)晶面立方体纳米Cu₂O材料的吸附热力学和吸附动力学性质与粒径之间的关系式. 实验结果与理论预测结果一致: 随着纳米Cu₂O粒径的减小, 吸附速率常数增大而吸附活化能和吸附指前因子减小; 标准摩尔吸附Gibbs自由能 Δ_a $G^{\rlap{-}0}_{m}$减小而标准吸附平衡常数ln $K^{\rlap{-}0}$、 标准摩尔吸附焓 Δ_a $H^{\rlap{-}0}_{m}$和标准摩尔吸附熵 Δ_a$S^{\rlap{-}0}_{m}$均增大, 且以上参数均与粒度的倒数具有较好的线性关系.     

Studies on Adsorption Behavior and Mechanism of Copper（ Ⅱ ） onto Amino Methylene Phosphonic Acid Resin

IntroductionThe adsorption ability of the functional poly-mer used to enrich metal ions is strong and the op-eration of the functional polymer is convenient.The polymer having adsorbed metal ions can be re-covered by means of an acid or an alkaline solutionand the recovered polymeric material can bereused.The adsorption ability of the polymer withvarious functional groups is different for differentmetals.Because nucleophilic atoms such as oxy-gen,nitrogen,sulphur and phosphorous atoms cancoord…