胡桃醌染发动力学及热力学研究

本文探究了天然染料胡桃醌与头发相互作用的吸附动力学及热力学,探究其染色机理。结果表明,染发过程中,头发对胡桃醌的吸附符合拟二级动力学模型,且染色速率和染色平衡吸附量均随着温度的升高而增大,在333 K下头发对胡桃醌的平衡吸附量最大,为18.957 mg/g。通过实验和理论的结合发现,Freundlich和Langmuir吸附理论均能较好的拟合吸附数据。但相比而言,Freundlich吸附理论可以更好地表述头发对胡桃醌分子的吸附作用。此外,吸附热力学数据表明吸附过程是自发吸热的物理吸附。ΔG0,说明头发对胡桃醌的吸附是自发进行的,ΔH0说明吸附为吸热反应,温度升高有利于吸附的进行。由Arrhenius方程求得活化能Ea为30.09 KJ/mol,表示吸附属于物理吸附。     

大孔树脂对八月瓜果皮总三萜的吸附特性研究

研究XDA-1型大孔树脂对八月瓜果皮总三萜的吸附特性。采用准一级动力学方程、准二级动力学方程、Van't Hoff方程和吸附等温方程研究吸附动力学与吸附热力学参数。结果表明,XDA-1大孔树脂对八月瓜果皮中总三萜的吸附符合准二级动力学方程描述;吸附等温线符合Freundlich等温吸附方程;吸附焓变ΔH=-1.2792 kJ/mol,为物理吸附;吉布斯自由能ΔG0,吸附过程是自发过程;吸附熵变ΔS0,表明吸附是熵值增加的过程。     

小球藻对U(VI)的生物吸附特性

试验研究了小球藻吸附U(VI)的过程,探讨了吸附机理、吸附热力学和动力学.考查了pH值、时间、U(VI)的起始浓度和温度等对吸附的影响.研究表明,pH值对小球藻的吸附效果影响较大,小球藻吸附U(VI)的最佳pH值为6,最大吸附量为2.7mg/g,吸附在5min内基本达到平衡.小球藻对U(VI)的吸附量与其浓度的正相关;温度在20℃-30℃时,对铀的吸附影响不大.实验结果还表明,吸附过程符合准二级动力学方程,其相关系数达0.99,该吸附为多种反应同时作用的复杂过程.U(VI)在小球藻上的吸附行为可以很好地用Langmuir等温方程来描述.     

大孔树脂富集迷迭香酸的静态吸附和解析研究

考察了AB-8、D101、X-5、NKA-II 4种大孔吸附树脂对迷迭香叶中迷迭香酸的静态吸附和解析性能。以吸附量、吸附率、解吸量、解析率为指标,筛选出较好的AB-8树脂。通过静态吸附和解析实验,研究了吸附时间和温度对AB-8静态吸附过程的影响,同时研究了一定温度和解析液中乙醇浓度对迷迭香酸静态解析过程的影响,并且从热动力学角度研究分析其吸附过程。结果表明,准二级反应动态模型、Langmuir方程和Freundlich方程适用于静态吸附过程,乙醇浓度是影响解析率的关键因素。     

红螺菌吸附铜的动力学与脱附研究

研究了红螺菌(Rhodospirillum)对Cu~(2 )的吸附动力学行为,在一定的条件下,吸附在45 min达到平衡,吸附平衡时最大吸附量为48.23 mg·g~(-1)。应用准一级和准二级反应动力学模型进行数据分析,结果表明菌体对Cu~(2 )的吸附符合准二级动力学模型。比较分析了多种脱附剂对菌体脱附,EDTA和柠檬酸是较有效的洗脱剂,脱附率分别为86.4％、66.9％;无机酸及无机盐对菌体的脱附效果很差,脱附率在20％左右。X-射线衍射分析表明,菌体吸附Cu~(2 )后没有形成新晶相,并且菌体部分晶相转变为非晶相。     

黑曲霉发酵菌渣对臧红T的吸附研究

将糖化酶发酵生产过程中产生的黑曲霉菌渣作为一种复合吸附剂进行了染料吸附研究,以挖掘其吸附潜力。首先对菌渣的理化性质进行了分析,然后以臧红T为模型染料,考察了几种因素(接触时间、溶液温度、吸附剂量、初始浓度和盐离子)对吸附的影响,并将所得数据用等温吸附方程、动力学方程和热力学方程进行了模型拟和。结果表明,吸附可在2 h内达到平衡,吸附过程符合准二级动力学模型,属于化学吸附,膜扩散模型比内扩散模型更适合解释吸附行为;温度对吸附有促进作用,吸附过程是一个自发的吸热反应;通过Langmuir方程可计算出最大单分子层吸附容量为166.67 mg/g,但Freundlich能更好的描述吸附行为,说明菌渣表面存在多个不同的吸附位点。此外,菌渣投加量和钠离子浓度均可影响吸附效果,染料去除率最高可达91%。     

土生鳞伞对Cd2+的吸附特性

以土生鳞伞（Pholiota terrestris Overh.）子实体为生物吸附剂吸附水溶液中的Cd2+,分析吸附剂用量、初始pH值、初始重金属浓度、反应时间这4个因素对吸附的影响,并采用Langmuir和Freundlich等温吸附模型及准一级、准二级动力学模型拟合土生鳞伞的生物吸附特性.结果表明:水溶液中Cd2+...     

榛子壳对亚甲基蓝吸附性能的研究

农林废弃物富含木质纤维素资源如纤维素、半纤维素、木质素等,被视为优质吸附剂,在环境保护方面广泛应用。本研究以鞍山地方特产榛子为原料,深入研究榛壳吸附剂对水体中的阳离子的吸附机理,以阳离子染料亚甲基蓝为例,通过实验室的静态实验,研究p H值、初始浓度、吸附时间和吸附温度对榛壳粉吸附剂对亚甲基蓝染料溶液的吸附性能影响,建立等温吸附模型和吸附动力学模型,并对热力学进行讨论分析,研究结果表明榛壳吸附剂的最佳吸附p H值为5.0~7.0间,最佳吸附时间为2 h。通过Langmuir等温吸附模型拟合得到的最大吸附量与实际值非常接近。准二级吸附动力学方程适合拟合榛壳粉亚甲基蓝的吸附过程,榛壳吸附剂吸附亚甲基蓝的过程为吸热过程。     

巴旦木壳基活性炭的制备及其对亚甲基蓝吸附的研究

以巴旦木壳为原材料，采用KOH活化法制备出了比表面积为1 763 m²/g的活性碳，通过SEM对样品结构进行表征，并研究了活性炭对亚甲基蓝的吸附效果。结果表明，KOH活化法制备的活性炭具有丰富的微孔结构，其对亚甲基蓝的最大平衡吸附量为524 mg/g，最佳吸附p H为6.0，吸附过程符合Langmiur方程描述的单分子吸附过程，其吸附动力学可用准二级动力学模型来表述。     

三氯蔗糖在大孔吸附树脂SP825上的吸附热动力学

采用静态吸附法,系统研究了三氯蔗糖在大孔吸附树脂SP825上的吸附热力学和动力学特性,为后续三氯蔗糖提取工艺的设计提供基础数据。实验结果表明:在283.15、293.15和303.15 K温度下,树脂SP825对三氯蔗糖的最大吸附量(每克湿树脂)分别为0.146、0.151和0.156 g。树脂SP825对三氯蔗糖的吸附平衡数据符合Lang-muir吸附等温方程,吸附过程为自发的物理吸附过程;并运用准二阶动力学模型描述了动力学过程,确定在实验条件范围内,吸附受颗粒内部传质速率的影响。     

麻栎壳斗染料在羊毛染色中的应用

本文研究了提取自麻栎壳斗的植物染料(麻栎染料)的耐酸、碱稳定性,染浴pH值及铝、铁离子等环保型媒染剂对其染毛织物效果的影响,并且探究了其染色动力学.研究表明,麻栎染料在强酸性染浴(pH=3)中对羊毛织物直接性好,染色后毛织物得棕色,也可采用铝离子、铁离子对直接染色后的毛织物进行后媒染,以得到不同色相的毛织物,尤其是铁后...     

Effects of Fulvic Acid on TNT Adsorption in Soil

In order to study the effect of fulvic acids (FA) on the migration of TNT in soil, batch experiments in which 2%, 5%, and 10% (w/w) of FA were added to soils were conducted. Adsorption kinetics and adsorption-desorption isotherms of TNT in soils were investigated, with results of the kinetics tests showing that the adsorption process could be divided into a fast and a slow stage and that FA could extend the adsorption time. Kinetic data were fit to pseudo first-order, pseudo second-order, Elovich, and intra-particle diffusion kinetic models. The fitting results showed that a pseudo second-order kinetic model best described the adsorption process, while Elovich and intra-particle diffusion kinetic models could accurately predict the adsorption at higher FA content. The adsorption-desorption isotherms were predicted using Linear, Freundlich, and Langmuir isotherm models. Results showed that the Freundlich model best described the adsorption-desorption process, and that FA increased adsorption capacity and enhanced the adsorption affinity. The hysteresis index suggested that FA could reduce the desorption of TNT in soil.     

Effects of temperature and pH on adsorption of basic brown 1 by the bacterial biopolymer poly(gamma-glutamic acid)

Poly(gamma-glutamic acid) (gamma-PGA), an extracellular polymeric substance (EPS) synthesized by Bacillus species, was explored to study its interaction with the basic brown 1 dye by conducting a systematic batch adsorption study as affected by two critical parameters, temperature and pH. Adsorption isotherms were closely predicted by Temkin equation among the eight isotherm models tested. The rate of adsorption was very rapid attaining equilibrium within 60 min and the kinetics were well described by both modified second-order and pseudo second-order models. Boyd's ion exchange model, which assumes exchanges of ions to be a chemical phenomenon, also fitted the kinetic data precisely. The adsorption rate increased with increasing solution temperature, however, a reversed trend was observed for the adsorption capacity. Changes in enthalpy, entropy and free energy values revealed dye adsorption by gamma-PGA to be an exothermic and spontaneous process involving no structural modification in gamma-PGA, whereas the activation energy of 37.21 kJ/mol indicated dye adsorption to be reaction-controlled. Following a rise in solution pH, the dye adsorption increased and reached a plateau at pH 5, while the maximum release of dye from spent gamma-PGA occurred at pH 1.5, suggesting a possible ion exchange mechanism. Ion exchange adsorption of basic dyes by gamma-PGA was further proved by the presence of two new IR bands at approximately 1600 and 1405.72 cm(-1), representing asymmetric and symmetric stretching vibration of carboxylate anion, for dye-treated gamma-PGA.     

不同炭化温度制备的蚕丝被废弃物生物炭对重金属Cd2+的吸附性能

以蚕丝被废弃物为原料,在300、500和700 ℃高温缺氧条件下热解炭化制备成3种生物炭(BC300、BC500和BC700).利用扫描电镜(SEM)、傅里叶红外光谱仪(FT-IR)、X-射线衍射仪(XRD)、比表面积分析仪等对其理化性质进行表征,并研究了不同温度下制备的生物炭对溶液中Cd²⁺的吸附特性.结果表明: 随着炭化温度上升,BET比表面积、pH、灰分均增大,生物炭表面形态结构越来越不规则.XRD结果显示:不同温度下获得的生物炭中均含有一定量的方解石,FT-IR光谱图上的峰主要为-OH和方解石典型的吸收峰;pH对生物炭吸附Cd²⁺的影响不大;Langmuir方程能更好地拟合3种生物炭对Cd²⁺的吸附等温过程,其最大吸附量分别为25.61、52.41和91.07 mg·g^-1.3种生物炭对Cd²⁺吸附过程均更符合准二级动力学方程,且BC700对Cd²⁺的吸附效果最佳.进一步研究离子浓度及阳离子共存对BC700吸附Cd²⁺的影响,结果显示: NaCl浓度越高,对Cd²⁺的吸附抑制越明显;共存阳离子中,Ca²⁺和Mg²⁺对Cd²⁺的吸附抑制更明显,而K⁺几乎无影响.因此,以蚕丝被废弃物制备的生物炭作为去除水体中Cd²⁺的吸附剂具有较强的应用潜力.     

Removal of thallium from aqueous solutions by modified Aspergillus niger biomass

The present study involves an investigation of various treated fungal biomasses of Aspergillus niger for the removal of thallium from aqueous solutions. Batch pH and kinetic studies were carried out to examine the effects of pH and contact time on the adsorption process. Among various pH values studied, the optimum pH was found to be between 4 and 5. The equilibrium time for Tl adsorption was found to be 6h and the rate of Tl adsorption was rapid in the initial hours. Both Lagergren's pseudo first-order model and Ho's pseudo second-order model well described the reaction kinetics. Batch adsorption experiments conducted at room temperature (22+/-1 degrees C) showed that the adsorption pattern followed the Freundlich isotherm model. Column studies using iron oxide-coated immobilized fungal biomass showed lower adsorption capacities compared to batch studies.     

Adsorption of methylene blue using green pea peels (Pisum sativum): A cost-effective option for dye-based wastewater treatment

Methylene blue (MB), a common toxic dye, is largely discharged from dyeing processes for acrylic, nylon, silk, and woolen fabrics in textile industries. While application of conventional removal processes like chemical precipitation, ion exchange, commercial activated carbon adsorption, etc often become cost-prohibitive, the adsorption of MB by abundantly available green pea peel (GPP: Pisum sativum) derived and acid-treated carbon (GPP-AC) has proved to be a cost-attractive option in the present study. The physicochemical and morphological characteristics of GPP-AC were examined with the help of XRD, BET surface area, SEM, and Fourier transform infrared spectrophotometry ((FT-IR) analysis. The influences of such adsorption parameters as initial dye concentration, pH, contact time, adsorbent dosage, agitation speed, particle size, and temperature were evaluated and optimized. The equilibrium contact time for maximum adsorption of MB on to GPPAC was found to be 7 h. The equilibrium data of the adsorption process were modeled by using the Langmuir, Freundlich, Temkin, and Dubinin-Raduskevich (D-R) isotherms. However, the adsorption equilibrium data were best described by the Langmuir Isotherm model, with a maximum adsorption capacity of 163.94 mg MB/g GPPAC at 30°C.     

Thermodynamics and kinetics of lysozyme adsorption onto two kinds of weak cation exchangers

The present work investigated the adsorption behaviors of lysozyme onto weak cation exchangers at different temperatures. The adsorption isotherm, adsorption thermodynamics and adsorption kinetics were studied. The results indicate that the adsorption of lysozyme onto acrylic acid copolymer based beads (Hydrolite D115) is spontaneous and exothermic, while that onto agarose based beads (CM Sepharose 6 Fast Flow) is also spontaneous, but endothermic. The pseudo second-order kinetic model fits well to the dynamic adsorption experimental data, and the kinetic results are also in concert with the adsorption thermodynamics.     

Adsorption kinetics of a basic dye from aqueous solutions onto apricot stone activated carbon

The preparation of activated carbon from apricot stone with H₂SO₄ activation and its ability to remove a basic dye, astrazon yellow 7GL, from aqueous solutions were reported in this study. The adsorbent was characterized by FTIR, BET and SEM, respectively. The effects of various experimental parameters, such as initial dye concentration, pH, adsorbent dosage and temperature were investigated in a batch-adsorption technique. The optimum conditions for removal of the basic dye were found to be pH 10, 6 g/l of adsorbent dosage and equilibrium time of 35 min, respectively. A comparison of three kinetic models, the pseudo first-order, second-order and diffusion controlled kinetic models, on the basic dye-adsorbent system showed that the removal rate was heavily dependent on diffusion controlled kinetic models. The adsorption isotherm data were fitted well to Langmuir and Freundlich isotherms. The adsorption capacity was calculated as 221.23 mg/g at 50 °C. Thermodynamics parameters were also evaluated. The values of enthalpy and entropy were 49.87 kJ/mol and 31.93 J/mol K, respectively, indicating that this process was spontaneous and endothermic. The experimental studies were indicated that ASC had the potential to act as an alternative adsorbent to remove the basic dye from aqueous solutions.     

Real-time determination of kinetics of adsorption of lead(II) onto palm shell-based activated carbon using ion selective electrode

In this study, the kinetics of adsorption of Pb(II) from aqueous solution onto palm shell-based activated carbon (PSAC) were investigated by employing ion selective electrode (ISE) for real-time Pb(II) and pH monitoring. Usage of ISE was very appropriate for real-time adsorption kinetics data collection as it facilitated recording of adsorption data at very specific and short time intervals as well as provided consistent kinetics data. Parameters studied were initial Pb(II) concentration and agitation speed. It was found that increases in initial Pb(II) concentration and agitation speed resulted in higher initial rate of adsorption. Pseudo first-order, pseudo second-order, Elovich, intraparticle diffusion and liquid film diffusion models were used to fit the adsorption kinetics data. It was suggested that chemisorption was the rate-controlling step for adsorption of Pb(II) onto PSAC since the adsorption kinetics data fitted both the pseudo second-order and Elovich models well.