木质素生物炭磺酸对水中阳离子染料的吸附性能与机制

以木质素磺酸钠(LS)为原料,采用浓硫酸一步氧化碳化的方法在60℃和210℃下分别制备了木质素生物炭磺酸SLBC-60和SLBC-210.SLBC-60磺酸基、羧基和酚羟基含量分别为1.66,1.40,4.41 mmol/g,而SLBC-210磺酸基、羧基和酚羟基含量分别为0.34,3.22,5.41 mmol/g.对...     

生物炭对阳离子染料的吸附性能研究进展

印染废水是一类重要的难降解工业废水,高效处理印染废水对于保护水生态环境和促进印染行业的可持续发展具有重要的现实意义。生物炭原料来源广泛、比表面积大、孔隙结构发达、制备成本低,对印染废水中的多种污染物均表现出良好的吸附潜能,其中采用生物炭吸附阳离子染料的研究近年来备受关注。概述了可用于制备生物炭的生物质原料选取原则,以及...     

头发对水中阳离子染料的吸附特性

采用静态吸附法对比了2种阴离子染料和2种阳离子染料在头发上的吸附能力,并测定了头发对阳离子染料碱性品红和亚甲基蓝的吸附动力学和吸附等温线,用准一级、二级动力学模型和Langmuir、Freundlich等温吸附模型进行拟合,计算了热力学参数。结果表明,头发对阳离子染料吸附能力较强,而对阴离子染料吸附能力较差,这主要和头发表面与染料之间电性引力有关。头发对碱性品红和亚甲基蓝在中、碱性条件下吸附效果较好,120 min达到吸附平衡,相同条件下,吸附量:亚甲基蓝>碱性品红。准二级动力学模型和Freundlich等温吸附模型能较好地描述头发对阳离子染料的吸附过程。吸附热力学参数计算结果表明,该吸附是一种自发、吸热、以多分子层吸附为主的物理过程。     

咖啡渣生物炭对水体中阳离子染料的吸附研究

以手冲深度烘焙咖啡渣作为原料,在800℃下制备生物炭.用典型阳离子染料亚甲基蓝(MB)进行咖啡渣生物炭(CWB)对阳离子染料的吸附研究.经吸附动力学模型拟合发现,CWB对阳离子染料的吸附符合Elovich模型(R2>0.9352),但与内扩散模型相关性小;等温吸附模型拟合发现,Freundlich和Redlich-Pe...     

水葫芦生物质炭的制备与染料吸附性能研究

以水葫芦为原料,采用限氧升温热解的方法制备了水葫芦生物质炭,研究热解温度对生物质炭理化结构与染料吸附性能的影响。结果表明,通过SEM、XRD、BET表征可以看出,在一定温度范围内,随温度升高生物质炭比表面积越大,孔隙结构越发达。当热解温度为500℃,生物质炭会有更多的含氧官能团以及较好的孔隙结构。随着热解温度的升高,生物质炭对染料吸附量先增加后有所降低,生物质炭对阳离子染料亚甲基蓝能达到更好的吸附效果,刚果红次之,甲基蓝的吸附效果一般。     

水葫芦生物质炭的制备与染料吸附性能研究

以水葫芦为原料,采用限氧升温热解的方法制备了水葫芦生物质炭,研究热解温度对生物质炭理化结构与染料吸附性能的影响。结果表明,通过SEM、XRD、BET表征可以看出,在一定温度范围内,随温度升高生物质炭比表面积越大,孔隙结构越发达。当热解温度为500℃,生物质炭会有更多的含氧官能团以及较好的孔隙结构。随着热解温度的升高,生物质炭对染料吸附量先增加后有所降低,生物质炭对阳离子染料亚甲基蓝能达到更好的吸附效果,刚果红次之,甲基蓝的吸附效果一般。     

生物发酵前处理生物炭对亚甲基蓝的吸附研究

原始生物炭由于比表面积小、官能团含量低,吸附性能受到影响。为提高生物炭的吸附性能,以棉秆生物质为基质,采用生物质微生物发酵前处理结合低温热空气碳化(TAT)技术制备高比表面积、高含氧官能团的生物炭,并通过扫描电镜(SEM)对发酵前后棉秆生物质的形貌进行表征,采用N₂吸附-脱附实验、傅里叶红外变换(FT-IR)、拉曼光谱对所制备生物炭的比表面积、官能团进行分析。结果表明,微生物发酵前处理所得的棉秆生物质表面附着大量微生物,微生物的分解作用破坏了生物质形貌结构,使所制备的生物炭的比表面积由0.01 m²/g提高至20.53 m²/g,C—O及其他含氧官能团含量大幅增加。吸附实验表明,微生物发酵前处理所得的棉秆基生物炭对亚甲基蓝(MB)的吸附容量为64.9 mg/g,是直接碳化制备的生物炭吸附容量的8倍;发酵前后棉秆生物质所制备的2种生物炭对MB的吸附均符合准二级动力学模型,其吸附过程受生物炭活性位点数和生物炭层状结构的控制;羟基在生物炭和MB之间的相互作用中起着关键作用,是主要的活性吸附位点。     

酸改性猪粪生物炭的制备及其对直接红23染料的吸附性能

以直接红23染料(DR23)溶液模拟印染废水,对比分析了酸改性前后猪粪生物炭对DR23的吸附特性与机理。通过静态吸附实验考察了DR23溶液的pH、初始浓度、吸附时间、吸附温度、吸附剂添加量等条件对吸附效果的影响,并确定了该吸附过程的吸附动力学和吸附等温线。研究发现,相比于未改性生物炭(PMB),酸改性后生物炭(PMB_acid)结构变得疏松多孔,表面官能团丰富,表现出更优的脱色性能,对DR23的吸附去除率最高可达96.10%,最大饱和吸附量为111.51mg/g,且在经过3次循环再生后,PMB_acid对DR23的去除率仍可达到88.31%;此外,pH对PMB_acid的脱色吸附性能影响较小。PMB_acid对DR23的吸附是一个受反应速率和扩散控制的复杂过程,符合于伪二级动力学模型和Langmuir等温吸附模型;PMB_acid对DR23的吸附机理取决于吸附剂的物理化学性质,其孔结构及各官能团通过不同的机制参与了生物炭对DR23的吸附过程。     

凹凸棒石粘土对阳离子染料吸附性能的研究

1 前言 凹凸棒石是一种含水富镁硅酸盐矿物,其理想的化学分子式为Mg_5Si_8O_2。(OH)_2(OH_2)_4·4H_2O。凹凸棒石具有层链状的结构特性,带有与沸石类似的孔道。由于其独特的晶体结构,因而具有很好的吸附脱色性能。本文采用我省皖东地区凹凸棒石粘上,经过高温焙烧活化处理,制成凹凸棒石粘土吸附剂,用于阳离子染料溶液的吸附脱色试验。试验考察了吸附剂的静态吸附容量、阳离子染料溶液的初始浓度、吸附剂颗粒的粒径、吸附剂加入量和吸附温度等因素对吸附过程的影响。     

Adsorption of cationic dyes from aqueous solution using hydrophilic silica aerogel via ambient pressure drying

In order to remove the organic dyes of textile waste water, the silica aerogel was successfully prepared by using E-40 as a novel precursor and then dried in ambient pressure. The synthesized sample was verified by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). After calcining, the hydrophilic silica aerogel (HSA) was used as adsorbent to remove Methylene Blue (MB), Malachite Green (MG), and Gentian Violet (GV) from aqueous solution. The effects of initial concentration of dyes and adsorbent dosage on the adsorption process were examined. It was found that HSA showed excellent adsorption capacities, the maximum percentage of removal dyes could reach 98%. Herein, the Langmuir, Freundlich and de Boer-Zwikker isotherm modes were employed to discuss the adsorption behavior. The results indicated that the de Boer-Zwikker model can effectively describe the adsorption behavior. Besides, the HSA could be utilized as the recyclable adsorbent in degradation experiment, after five cycles, no obvious loss of adsorption capacity was found. As an efficient, low-cost, environmental friendly and recyclable adsorbent, silica aerogel is expected to be used for dyes removal.     

Adsorption of cationic dyes from aqueous solution using hydrophilic silica aerogel via ambient pressure drying

In order to remove the organic dyes of textile waste water, the silica aerogel was successfully prepared by using E-40 as a novel precursor and then dried in ambient pressure. The synthesized sample was verified by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). After calcining, the hydrophilic silica aerogel (HSA) was used as adsorbent to remove Methylene Blue (MB), Malachite Green (MG), and Gentian Violet (GV) from aqueous solution. The effects of initial concentration of dyes and adsorbent dosage on the adsorption process were examined. It was found that HSA showed excellent adsorption capacities, the maximum percentage of removal dyes could reach 98%. Herein, the Langmuir, Freundlich and de Boer-Zwikker isotherm modes were employed to discuss the adsorption behavior. The results indicated that the de Boer–Zwikker model can effectively describe the adsorption behavior. Besides, the HSA could be utilized as the recyclable adsorbent in degradation experiment, after five cycles, no obvious loss of adsorption capacity was found. As an efficient, low-cost, environmental friendly and recyclable adsorbent, silica aerogel is expected to be used for dyes removal.     

Adsorption of dyes from aqueous solution by coals, chars, and active carbons

Adsorption of two acidic dyes (amaranth red and metanil yellow) and a basic dye (methylene blue) from aqueous solution has been studied using a wide range of American coals and chars. The adsorption capacity of coals and chars has been compared with commercially available active carbons. The amount of dye removed from solution by raw coals is made up of two parts, one due to interaction with some mineral constituents and the other due to adsorption on the porous surface. There are some indications that pyrite and soluble alkali salts are the reactive minerals. When the coals are washed by refluxing in distilled water for 8 h, reproducible adsorption capacity is obtained. With washed coals, good correlation between the nitrogen BET surface area and dye adsorption capacity is observed. Except for lignites, adsorption of dyes is not influenced by the oxygen groups on the surface. Chars show enhanced capacity over coals, where under the most favourable conditions adsorption approached 25% of the active carbon capacity. The initial rate of adsorption of dye from solution by coals, chars and active carbons has been found to be dependent on the square root of time.     

Adsorption of cationic pesticides (diquat and paraquat) from aqueous solution by activated carbon

Adsorption of diquat and paraquat cationic pesticides from aqueous solution studied on three different activated carbons varying in N₂-BET surface area from 660 m²/g to 1280 m²/g suggests that the rate limiting step for removal of these pesticides in agitated non-flow systems is one of intraparticle transport of the solute in the pores and capillaries of the adsorbent. The sorption rates for both adsorbates may be characterized by diffusion coefficients, D, calculated in the usual manner assuming the flux of diffusion to be proportional to the concentration gradient. The resultant values for D vary fairly inversely proportionately with the N₂-BET surface area of an activated carbon for an individual adsorbate. Adsorption capacities on active carbon of diquat and paraquat from water vary from ~18 to 36% and ~6 to 14% respectively by weight of active carbon, depending upon the surface area of the carbon. These values are fairly attractive, especially for diquat, from a practical point of view of removing trace quantities of these pesticides. Thermodynamic studies indicate that the rate of removal of these pesticides by active carbon is an endothermic process which is in agreement with a suggested intraparticle transport rate control mechanism; however, the equilibrium position is governed by an exothermic reaction, as is expected for adsorption. Competitive adsorption studies of diquat and paraquat when present as an equimolar mixture, which should indicate the relative affinity of the surface available for each of the two adsorbates, suggest that different sites on the active carbon surface probably adsorb both adsorbates in a different manner.     

Multifunctional amphoteric resin to remove both anionic and cationic dyes from aqueous solution

This study reports the synthesis and characterization of a new amphoteric resin, which can be used for the removal of both cationic, methylene blue (MB) and anionic dyes, reactive red-120 (RR-120). The amphoteric resin was characterized by ATR-FTIR, SEM–EDX, TGA/DTA, DLS, BET analysis and also its surface pHpzc was determined. The prepared resin has micro porous structure and its particle size was at the nano level. The prepared amphoteric resin showed high removal affinity for MB in both acidic and basic medium, while for RR-120 high removal affinity in acidic medium. Moreover, it was observed that the amphoteric resin has exhibited almost 100% dye removal up to 600 ppm for MB and up to 300 ppm for RR-120, respectively. The adsorption behavior of both dyes on the amphoteric resin is in agreement with the Langmuir isotherm and the pseudo-second order kinetic model and also electrostatic interaction is dominant in adsorption. Its capacity was slightly low for the MB than that of the commercial activated carbon, but higher for the RR-120. Furthermore, it was observed that the amphoteric resin almost did not lose its high removal efficiency in the concentrated matrix environment for both dyes. After five repeated adsorption–desorption cycles, the high removal efficiency of the resin for the MB (almost 100%) unchanged, but for the RR-120 decreased to 83%.     

硫酸改性小麦秸秆生物炭对氨氮吸附特性研究

以小麦秸秆制备生物炭(550℃)、并以硫酸作为改性剂制备得到改性生物炭材料,通过SEM、BET、元素分析、FTIR、Boehm滴定等材料学方法,发现改性后,表面出现显著的规则孔穴结构,孔径分布在0.6~1.0 nm出现集聚;比表面积较未改性组增加54%,达189.2 m~2/g;酚羟基类酸性官能团增加522%,达0.56 mmol/g。吸附性能实验显示,经济改性条件是70%硫酸反应24 h;等温吸附曲线更符合Langmuir模型,吸附量增加69%,达19.12 mg/L,吸附能力显著提高。     

乳状液膜分离过程中的结构演变

以乳状液膜分离H2S,借助激光粒度仪、Zeta电位仪、显微镜等手段研究乳化剂类型及浓度、内相浓度、搅拌速率和时间等因素对液膜粒径的影响。结果表明,搅拌速率及乳化剂类型对其影响最大;4种乳化剂内相粒径按照Span 80、T152、T153及T154的顺序依次增加。时间效应显示,放置24 h后,内相之间存在合并现象。通过将搅拌速度、叶轮直径、液膜密度及界面张力定义为一个Webber数(We=n2DTu3ρ/σ),能够建立其与内相粒径之间的一一对应关系,这将用于预测液膜粒径的范围。该研究对精确构建ELM分离过程中的传质模型提供了直接数据。     

Counterion effects on the aqueous solution viscosity of cationic surfactants

The effect of varying counterion structure on the aqueous solution viscosity of various cationic surfactants was systematically examined for compounds of the type: CH₃(CH₂) _x N(CH₃)₃YAr. Ar = functionally substituted aryl moieties and Y = carboxylate (CO₂ ⁻), sulfinate (SO₂ ⁻) or sulfonate (SO₃ ⁻). Aqueous solution viscosity, which is assumed to be a measure of ion pair stability, is clearly affected by anion and cation structure, temperature, concentration and stoichiometry. An ortho substituent to the anionic functionality, e.g. hydroxyl, substantially increases ion pair stabilization. Ion pair stability is also enhanced by increasing the solution concentration, decreasing temperature, increasing cation/anion ratio or by increasing the alkyl (x) chain length.