枸杞杆制活性炭对亚甲基蓝的吸附研究

以宁夏农业废弃物枸杞杆为原料,用不同的活化剂分别制备磷酸-活性炭（P-AC）、氢氧化钾-活性炭（K-AC）、磷酸-氢氧化钾-活性炭（P-K-AC）,利用比表面积测试（BET）、X射线衍射（XRD）、红外光谱（FT-IR）、扫描电镜（SEM）解析活性炭的孔结构和表面特性,并探究活性炭对水溶液中亚甲基蓝（MB）的去除效果。研究结果表明：P-K-AC比P-AC、K-AC具有更大的比表面积（1 519.84 m²/g）和总孔体积（0.81 cm³/g）,P-AC、K-AC、P-K-AC的平均孔径分别为5.28、2.58、1.99 nm,P-K-AC以微孔为主,K-AC、P-AC均为介孔。3种活性炭表面均分布着丰富的含氧官能团和大量的无定型碳,为吸附MB提供了活性位点。在25 ℃条件下,将10 mg的P-AC、K-AC、P-K-AC分别加入50 mL质量浓度为100 mg/L的MB溶液中用于吸附MB实验。结果表明：P-K-AC的吸附效果最好,吸附率达到95%、吸附量为480.81 mg/g;其次是K-AC,吸附量为352.26 mg/g;P-AC吸附量最小,为225.01 mg/g。P-AC,K-AC、P-K-AC对MB的吸附过程都符合伪二级动力学模型、颗粒内扩散模型和Langmuir等温吸附模型。     

改性活性炭对亚甲基蓝的吸附性能及机理

以价廉易得的商业炭为原料,采用氢氧化钾为活化剂,制备出改性微孔活性炭。对其进行了表征分析,并将其用于吸附印染废水中的亚甲基蓝(MB)。结果表明,经活化改性后的活性炭孔径分布均匀,平均孔径为1.2 nm,比表面积高达2 380 m~2/g(比商业炭提高了58.7%)。改性活性炭对MB的吸附过程符合Redlich-Peterson等温吸附模型,其吸附机理符合Langmuir模型的可能性较大,吸附动力学特征符合准2级动力学方程,吸附速率主要受颗粒内活性位点吸附步骤控制。改性活性炭在在室温下对MB的最大吸附量可达305.0 mg/g。吸附过程是自发进行的,温度的升高有利于吸附过程的进行与吸附量的提高。     

玉米淀粉/羧甲基纤维素生物复合凝胶的制备及吸附行为研究

以玉米淀粉与羧甲基纤维素（CMC）为骨架，以丙烯酸（AA）、丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）为单体制备复合凝胶，对复合凝胶材料进行表征。以亚甲基蓝（MB）为吸附质，考察复合凝胶吸附剂对阳离子染料吸附过程的动力学和热力学行为，分析阳离子强度、水体pH值、染料初始质量浓度等对吸附剂吸附性能的影响。结果表明：玉米淀粉-CMC-g-AA-AM-AMPS凝胶是一种表面多孔的吸附材料，其比表面积为24.939 7 m2/g，平均吸附孔径为8.668 2 nm。凝胶对MB的吸附过程与准二级动力学模型和Langmuir模型拟合较好，属于单分子层的化学吸附。阳离子对凝胶吸附MB有明显抑制作用，抑制效果为Al3+>Ca2+>Na+。随着离子强度的增加，抑制作用越明显。在投加量为0.1 g、温度为298 K、pH值为11.0、MB初始质量浓度为2 000 mg/L条件下，吸附剂最大吸附量达到1 938.82 mg/g、去除率为96.94%，能有效去除MB。     

文冠果活性炭水凝胶的制备及其吸附性能研究

以丙烯酰胺(AM)、丙烯酸(AA)和文冠果活性炭(XSBAC)为原料,制备文冠果活性炭水凝胶(XSBACH),并应用于亚甲基蓝(MB)的吸附。利用比表面积分析仪(BET)、红外光谱仪(FTIR)等设备对XSBACH的结构进行表征。探讨了亚甲基蓝溶液的浓度、pH值、温度及时间对XSBACH吸附量的影响。结果表明,在吸附时间为120 min, MB溶液浓度为500 mg/L,反应温度为303 K时,XSBACH对MB的吸附量最大,为295.36 mg/g。吸附过程符合伪二级动力学模型,等温吸附过程符合Langmuir吸附等温模型,在303～323 K温度范围内,XSBACH吸附MB的吉布斯自由能ΔG°<0、焓变ΔH°<0、熵变ΔS°<0,表明XSBACH吸附MB是一个自发的放热过程。     

GO/GA-g-PAMPS复合水凝胶的制备及阳离子染料吸附性能

以自制氧化石墨烯（GO）和阿拉伯胶（GA）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS)为原料,采用一步水热反应法制备了GO/GA-g-PAMPS新型复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶结构进行了表征。研究了GO浓度、溶液pH、染料初始浓度、吸附时间、吸附温度对阳离子染料亚甲基蓝（MB）和结晶紫（CV）吸附性能的影响。结果显示：水凝胶对阳离子染料具有较好的吸附效果,在GO浓度为0.3mol/mL,凝胶用量为0.05g,溶液pH为7,温度为50℃,染料初始浓度为200mg/L时,凝胶对MB和CV的吸附量和吸附率分别为395.68、381.70mg/g和98%、96%。凝胶经过5次循环使用后,对MB和CV的吸附率仍能达到82.6%和81.2%。吸附等温线和动力学研究表明,凝胶对MB吸附更符合Freundlich模型,对CV的吸附更符合Langmuir模型,准二级动力学模型能更好地描述两种阳离子染料的吸附过程。热力学研究表明水凝胶对两种染料吸附是自发、吸热和混乱度增加的过程。     

ZnS/AC复合材料的制备及其对铀酰离子的吸附性能

采用化学沉淀法制备了活性炭负载纳米硫化锌的复合材料ZnS/Ac，利用SEM、EDS、XRD、FTIR、BET等手段对该复合材料进行了表征分析。研究了ZnS/Ac对水溶液中铀酰离子的吸附性能，探讨了吸附时间、初始铀酰离子浓度、pH值、吸附剂投加量、温度等因素对吸附性能的影响，并对吸附过程进行了热力学和动力学模拟，探讨了吸附机理。结果表明：ZnS/Ac的比表面积为201.1961 m2/g，比活性炭的比表面积（165.0240 m2/g）明显增大，平均孔径为4.70 nm，孔容为0.038 cm3/g。在初始质量浓度为35 mg/L，pH=6，吸附时间为120 min，投加量为10 mg，处理温度为50 ℃的条件下，吸附剂对铀酰离子的吸附量为64.4736 mg/g。吸附过程符合准二级动力学方程和Langmuir 吸附等温线模型，热力学参数<0、>0、>0，表明该吸附是一个自发的吸热过程。     

向日葵制活性炭对亚甲基蓝的吸附研究

含有亚甲基蓝（MB）的废液直接排放会造成严重的水体污染。为研究生物质活性炭对MB的吸附性能,以农业废弃物向日葵为原料、磷酸（H₃PO₄）为活化剂,制备粉状活性炭（PAC）和块状活性炭（BAC）,并研究PAC对MB的吸附性能。利用比表面积测试（BET）、X射线光电子能谱（XPS）、X射线衍射（XRD）、红外光谱（FT-IR）和扫描电镜（SEM）等方法解析活性炭的孔结构和表面特性。结果表明：活性炭前驱体的形状对活性炭的微观结构有较大的影响。PAC比BAC具有更大的比表面积（分别为701.95 m²/g和566.49 m²/g）和总孔体积（分别为2.23 cm³/g和1.04 cm³/g）;PAC和BAC的平均孔径分别为7.31 nm和12.66 nm,均具有介孔材料的结构特性。两种活性炭表面均分布着丰富的含氧官能团和大量疏松的无定形碳,而存在的偏磷酸盐对孔隙起到支撑作用,这为MB的吸附提供了更多的活性位点和吸附通道。在25 ℃、pH为8、PAC用量为50 mg条件下,PAC对100 mL质量浓度为200 mg/L的MB溶液的吸附效果最好,吸附率达到72.2%。吸附过程符合伪二级动力学模型、颗粒内扩散模型和Langmuir等温吸附模型。     

活化氧化石墨烯的制备及对甲基橙的吸附

为了提高氧化石墨烯(GO)的比表面积和吸附性能,采用氢氧化钾对GO进行高温固相活化,制备出活化氧化石墨烯(GOKOH),并将其用于对水中阴离子染料甲基橙(MO)的吸附研究。结果表明,GOKOH的比表面积可达672.48 m2/g。GOKOH能在较宽的p H范围内实现对MO的高效去除,去除率高达94.87%,吸附平衡时间约为150 min。准一级和准二级动力学拟合的理论平衡吸附容量分别为549.87 mg/g和549.45 mg/g,Langmuir模型的饱和吸附容量为632.91 mg/g。该吸附过程受边界层扩散与颗粒内扩散两个步骤控制,符合二级动力学模型和Langmuir模型,并主要以化学吸附为主。     

榴莲壳生物炭对磺胺嘧啶的吸附性能

以榴莲壳为原材料,制备了榴莲壳生物炭（biochar,BC）,以磷酸为活化剂,在碳化温度为350℃、浸渍比为2.5∶1（磷酸∶生物质,质量比）的条件下,制备了活化榴莲壳生物炭（activated durian shell biochar,DBC）,并探究二者对磺胺嘧啶（sulfadiazine,SDZ）的吸附作用。通过单因素实验探究了DBC投加量、溶液pH、初始浓度、吸附温度对水中SDZ的去除影响,并用正交实验确定了DBC对SDZ吸附的最优条件。在生物炭的投加量为1.2g/L、SDZ初始浓度为10mg/L、溶液pH为4时,SDZ最大去除率最高。利用吸附等温模型（Langmuir、Freundlich）和吸附动力学模型（准一级动力学、准二级动力学）,探究DBC对SDZ的吸附特性,并进行了比表面积及孔径分析、扫描电镜（SEM）、傅里叶红外光谱（FTIR）的表征分析。结果表明,与BC相比,DBC有丰富的微孔结构,比表面积达1224.635m²/g,含氧官能团数量增加,为SDZ的吸附提供了更多的吸附位点,同时Langmuir吸附等温模型可以较好地描述DBC对SDZ的吸附等温过程,吸附动力学过程更符合准二级动力学方程。因此,磷酸活化榴莲壳生物炭可以作为一种高效的吸附剂去除水中的磺胺嘧啶。     

膨润土-活性炭复合吸附剂对锰离子的吸附

以膨润土和活性炭为原料制备了复合吸附剂并将之应用于含锰离子废水的吸附。考察了不同条件下该吸附剂对水体中Mn（Ⅱ）的去除效果,并研究了吸附动力学特征和等温吸附过程。结果表明膨润土和活性炭复合吸附剂对Mn（Ⅱ）具有优良的吸附能力,在25 ℃下,当投加量为4 g/L、Mn（Ⅱ）初始质量浓度为50 mg/L、溶液pH为6时,吸附180 min,吸附率为93.2%。准一级、准二级动力学和内扩散模型用来拟合吸附过程,结果表明准二级动力学符合该吸附过程,吸附速率常数为0.003 6 g/（mg·min）,内扩散过程不是吸附的限速步骤,还存在吸附机制的制约。用Langmuir和Freundlich模型描述吸附等温过程,结果得出该吸附过程服从Langmuir吸附,饱和吸附容量为27.781 mg/g。     

Preparation of hierarchical magnesium silicate with excellent adsorption capacity

Magnesium silicate (MS) is a widely used adsorbent, and much work has been done to control the surface morphology of MS to improve its adsorption capacity. In this work, hierarchical MS was prepared by combining hydrothermal process with freeze drying technique for potential application in adsorption. Firstly, the MS hydrogel was prepared by hydrothermal process, followed by replacement of water in hydrogel by tert-butyl alcohol. Finally, the MS was obtained by freeze drying. The prepared MS exhibited a rough and porous hierarchical structure having BET specific surface area and total pore volume of 530?m²/g and 0.90?cm³/g, respectively. MS was further used for methylene blue (MB) adsorption in aqueous solution and the adsorption data exhibited good correlation with the Langmuir adsorption isotherm model. The maximum adsorption capacity for MB was found to be 526?mg/g, far higher than the conventional adsorbents that popularly reported in literature. In conclusion, this work provides a novel route to prepare adsorbents with high adsorption performance.     

Acid Black 172 dye adsorption from aqueous solution by hydroxyapatite as low-cost adsorbent

The Acid Black 172 dye adsorption on the uncalcined hydroxyapatite nanopowder was investigated. The hydroxyapatite prepared by wet coprecipitation method has high specific surface area of 325 m²/g and crystal sizes smaller than 70 nm. The batch adsorption experiments revealed that under the optimum adsorption conditions (pH 3, hydroxyapatite dosage 2 g/L, initial dye concentration 400 mg/L and temperature 20 °C) the dye removal efficiency was 95.78% after 1 h of adsorption. The adsorption kinetics was best described by the pseudo-second order kinetic model. The intraparticle diffusion model shows that intraparticle diffusion is not the sole rate-limiting step; the mass transfer also influences the adsorption process in its initial period. The Langmuir isotherm model best represented the equilibrium experimental data, and the maximum adsorption capacity (q _m ) was 312.5 mg/g.     

SMA-β-环糊精聚合物制备及其对水中亚甲基蓝的吸附性能

用β-CD与苯乙烯-马来酸酐交替共聚物(SMA)反应,制备了β-CD质量分数为49.8%的水不溶性SMA-β-CD,并用IR、元素分析及热分析表征。以SMA-β-CD为吸附剂,研究了25℃下SMA-β-CD对水中亚甲基蓝(MB)的吸附性能。结果表明,吸附性能随体系p H升高而提高,吸附在120 min内达到平衡。固液比为0.25g/L时,SMA-β-CD对20 mg/L的MB的吸附率为100%;固液比为0.5 g/L时,对213.6 mg/L的MB吸附率达98%。SMA-β-CD对MB的吸附符合Langmuir模型,由Langmuir方程求得的最大吸附量为316.4 mg/g;吸附符合拟二级动力学模型。     

Removal of methylene blue from aqueous solutions by poly(2-acrylamido-2-methylpropane sulfonic acid-co-itaconic acid) hydrogels

In this study, removal of methylene blue (MB) from aqueous solution by poly(AMPS-co-IA) hydrogels was examined by batch equilibration technique. The effects of monomer ratio, concentration of initiator and crosslinker, pH, adsorption time, initial dye concentration and adsorption temperature on the removal of MB were studied. The results show that the removal of MB was highly effected by preparation conditions of hydrogel. The maximum removal was observed at 10/90 IA/AMPS monomer ratio, 1.0% KPS, and 10.0% MBAAm concentrations. Removal of MB was strongly affected by pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of MB on hydrogel followed pseudo-second-order kinetics. It was found that the adsorption isotherm of the MB fit Langmuir-type isotherms. From the Langmuir equation, the adsorption capacity was found as 1,000 mg/g for MB dye. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. Ten adsorption—desorption cycles demonstrated that the hydrogels were suitable for repeated use without considerable change in adsorption capacity. The results revealed that this hydrogels have potential to be used as an adsorbent for the removal of MB from aqueous solution.     

Studies on castor seed shell as a sorbent in basic dye contaminated wastewater remediation

The potentialities of castor seed shell (CSS), a waste agricultural by-product, in the remediation of water, contaminated with Methylene Blue (MB), a basic dye, were investigated in the present study. The CSS was ground and washed, thoroughly, to remove any water extractable constituents. The dried CSS was reground, sieved and used in series of agitated batch adsorption experiments. The experiments were conducted to assess the effect of two process variables i.e. initial MB concentration and CSS dosage on the sorption process. The equilibrium sorption isotherm was studied using the two widely used isotherm models (i.e. Freundlich and Langmuir isotherm models). The results from the isotherm studies showed that the process of sorption of MB occurred on a heterogeneous surface of the CSS. The sorption capacity of the CSS, as obtained from the Langmuir plot was 158 mg/g. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order and chemisorptions pseudo-secondorder kinetic models. The sorption process obeyed the pseudo-second-order kinetic model more than the pseudo-first order; hence the mechanism of the sorption process was analysed further using this kinetic model. The application of the intraparticle diffusion model to determine the rate limiting step showed that intraparticle diffusion is not the singular rate limiting step in the sorption of MB onto CSS. The role of chemisorptions in the mechanism of sorption was established by an empirical relationship between the pseudo-second-order rate constant, K, and the initial MB concentration. The results of this relationship showed that pseudo-second-order chemisorptions are important in the sorption process.     

硼碳氮多孔材料的制备及其吸附再生性能研究

硼碳氮(BCN)多孔材料因其具有高的比表面积、优异的化学稳定性而被认为是一种优异的吸附材料。本文以废弃椰壳、硼酸(H₃BO₃)和尿素(CO(NH₂)₂)为原料,采用冷冻干燥法制备多孔生胚,并在NH₃气氛下通过高温固相反应法在不同的反应温度下合成BCN多孔材料。结果表明,随着反应温度的升高,BCN多孔材料孔径逐渐变大,当反应温度为950 ℃时平均孔径为2.1 nm。将BCN多孔材料用于吸附水中孔雀石绿(MG)有机染料,其最大吸附量可达1 239.8 mg·g^-1,5次循环再生后吸附量平均值仍高达1 138.6 mg·g^-1,说明BCN多孔材料具有优异的循环吸附性能。采用Langmuir和Freundlich等温吸附模型、准一级和准二级吸附动力学模型研究了浓度、吸附时间和平衡吸附量之间的关系。结果表明,BCN多孔材料的吸附与准二级吸附动力学模型吻合,其对MG的吸附属于均匀表面单层分子的Langmuir等温吸附。BCN多孔材料展现出优异的吸附能力,是一种非常有应用前景的新型吸附剂。     

Removal of methylene blue dyes from wastewater using cellulose‐based superadsorbent hydrogels

Superadsorbent cellulose‐graft‐acrylic acid (C‐g‐AA) hydrogels were successfully prepared via free radical polymerization in phosphoric acid solution. Phosphoric acid solution provides a homogeneous reaction system. The C‐g‐AA hydrogels have a porous network inner structure with cellulose as the backbone. The introduced carboxyl groups enable the C‐g‐AA hydrogels with good swelling property (swelling ratio 7327%) and excellent MB adsorption capacity (equilibrium adsorption amount 2197 mg g^?1). The dynamic swelling behaviors of the hydrogels were tested, water intake of hydrogels followed a non‐Fickian type diffusion. The effects of mole ratio of AA to cellulose, the pH of adsorption medium and the initial MB concentration on dye adsorption capacity of hydrogels were investigated. The adsorption isotherm and kinetics fit the Langmuir model and the Pseudo‐second‐order model well, respectively. Desorption was carried out in weak acid solution and 70% MB could be removed, suggesting the C‐g‐AA hydrogels had the potential for reuse. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers