改性花生壳对苯酚的吸附

以花生壳为原料,使用环氧氯丙烷、二甲胺及吡啶,以N,N-二甲基甲酰胺为反应介质改性花生壳。结果表明:改性花生壳对苯酚的去除效果优于未改性花生壳。在实验条件下,吸附剂的吸附量在溶液pH为9,吸附时间为120 min时达到最大;溶液离子强度对吸附的影响较大。分析了该反应体系的动力学和热力学参数,改性花生壳吸附苯酚过程拟用准二级动力学模型处理,计算得出平衡吸附量与实验值相符。改性花生壳对苯酚的吸附符合Langmuir和Freundlich等温模式,R2均大于0.98,Qmax在84.49～108.76 mg/g之间,Freundlich模式的吸附强度n值在1.211～1.262之间,热力学参数△G、△H、△S表明改性花生壳对苯酚的吸附过程是自发、吸热过程。     

鸡蛋壳废料对水体中Cr(Ⅵ)的吸附特征与机理

利用鸡蛋壳废料对水中的Cr(Ⅵ)进行吸附处理,研究溶液p H、振荡时间、投加量和温度对鸡蛋壳废料吸附水体中Cr(Ⅵ)的特征和吸附机理。结果表明,在含有1 mg/L的Cr(Ⅵ)溶液的100 m L吸附体系中,鸡蛋壳废料可在30 min内完成吸附过程。溶液p H=2.5时,吸附量最大。鸡蛋壳投加量为1.0 g时,平衡吸附容量为0.0917 mg/g。利用鸡蛋壳去除水中Cr(Ⅵ)的最佳工艺参数为振荡时间30 min,初始p H为3.0,投加量2.0 g,体系温度35℃。鸡蛋壳对Cr(Ⅵ)的吸附过程用Langmiur和Freundlich方程能较好拟合,其中理论饱和吸附量在20℃、30℃和40℃时分别为0.1944、0.2034和0.2096 mg/g。吸附的焓变为8.76×10-3k J/mol,熵变为-45.96 J/(mol·K),吉布斯自由能变均为正值,变化范围是4.357~9.693 k J/mol。鸡蛋壳对Cr(Ⅵ)的吸附过程主要为物理性的单分子层和多分子层吸附。     

改性核桃壳对Cr(Ⅵ)的吸附

采用甲醛-硫酸改性法制备改性核桃壳吸附剂,利用静态吸附法研究了改性核桃壳对模拟废水中低浓度Cr(Ⅵ)的吸附性能,并采用SEM和FTIR技术对改性前后的核桃壳进行表征。表征结果显示,改性后的核桃壳表面更粗糙,孔隙轮廓更清晰,更有利于对Cr(Ⅵ)的吸附。实验结果表明:在初始Cr(Ⅵ)质量浓度为20 mg/L、初始废水p H为1、吸附温度为30℃、吸附时间为100 min、改性核桃壳加入量为24 g/L的条件下,改性核桃壳对Cr(Ⅵ)的去除率为98.4%,高于在相同条件下未改性核桃壳对Cr(Ⅵ)的去除率(93.1%);改性核桃壳对Cr(Ⅵ)的吸附更符合Freundlich等温吸附方程,对Cr(Ⅵ)的吸附行为满足拟二级动力学方程。     

花生壳、大豆壳和柚子皮对Cr3+、Cu2+和Ni2+的吸附研究

采用农林废弃物花生壳、大豆壳、柚子皮对重金属离子Cr3+、Cu2+和Ni2+进行吸附研究,探讨反应时间、吸附剂用量、pH、重金属离子初始浓度以及温度对吸附的影响.结果表明:柚子皮对Cr3+、Cu2+、Ni2+的吸附效果优于花生壳和大豆壳,其在20℃、pH 5.00、10.0 mg/kg条件下,反应360 min,Cr3+、Cu2+、Ni2+的吸附率分别可达83.20％、84.50％、59.10％;花生壳、大豆壳和柚子皮对Ni2+的吸附率远低于Cr3+和Cu2+;花生壳、大豆壳和柚子皮对Cr3+、Cu2+、Ni2+的吸附动力学可以用准二级动力学方程描述;吸附率随初始重金属离子浓度增加而降低,其吸附等温线可以用Langmuir方程描述;在一定范围内,吸附率随吸附剂用量增加而增加;溶液初始pH在2～5时,吸附率随pH增大而增加;Cu2、Ni2+的吸附量随温度的上升而逐渐减少,但Cr3+的吸附量随着温度的上升而略增加.     

花生壳活性炭对水中荧光素钠的吸附及动力学

H3PO4活化花生壳炭(750℃)为吸附剂,荧光素钠为吸附质.考察了炭化温度、投加量、pH、离子强度、吸附时间以及初始浓度对花生壳活性炭吸附荧光素钠的影响.重点研究了花生壳活性炭对荧光素钠的等温吸附特征,并利用准一级、准二级动力学模型和颗粒内扩散方程对花生壳活性炭吸附荧光素钠的动力学过程进行了分析.结果表明,本实验条件下,Langmuir等温吸附模型能很好地描述花生壳活性炭对荧光素钠的吸附效果,吸附强度因子a为正值,表明吸附过程在本实验条件下可自发进行.通过带入实验数据校对得出准二级动力学方程能更好地描述花生壳活性炭对水中荧光素钠的吸附动力学过程.     

牡蛎壳粉末投加UASB反应器的运行特性

采用牡蛎壳粉末作为UASB反应器的辅助介质,探讨了牡蛎壳钙盐的溶出特性,系统考察了运行期中牡蛎壳粉末添加方式、进水有机负荷、水力停留时间等因素对反应器出水COD、碱度与pH的影响,分析了污泥比产甲烷活性变化。结果表明,当初始pH从5到9变化时,牡蛎壳粉末溶出Ca2+浓度为40~65 mg/L,平衡pH稳定在7.7~8.0;当进水COD负荷从3.4 kg/(m3·d)逐渐增至7.0 kg/(m3·d)、牡蛎壳粉末投加量从1.5 g/d逐渐增至3.2 g/d时,与未投加的反应器相比,投加牡蛎壳粉末反应器的启动周期缩短了10%左右,COD去除率与比产甲烷活性分别提高了13.3%和22%。投加牡蛎壳粉末可有效提供碱度,加快污泥的颗粒化进程。     

Dry reforming of methane over oil palm shell activated carbon and ZSM-5 supported cobalt catalysts

In this study, cobalt supported oil palm shell activated carbon (Co/OPS-AC) and ZSM-5 zeolite (Co/ZSM-5) catalysts have been prepared for dry reforming of methane. Cobalt ratios of 6.0 and 14.0 wt% were deposited via wet impregnation method to the OPS-AC and ZSM-5 catalysts. The catalysts were characterized by XRD, N₂ adsorption--desorption isotherms, BET surface area, SEM, FESEM-EDX, TPR-H₂, and TPD-NH₃. The dry reforming of methane was performed using a micro reactor system under the condition of 10,000 ml/h.g-cat, 3 atm, CH₄/CO₂ ratio of 1.2:1.0 and temperature range from 923 K to 1023 K. The gaseous products were analyzed by gas chromatography (GC) with thermal conductivity detector (TCD) and further quantified to determine the conversions of CH₄ and CO₂, and the yields of CO and H₂. Experimental results revealed both catalysts exhibited lower conversions of CO₂ and CH₄ with the increase in temperature from 923 K to 1023 K. The reduced conversions may be due to the formation of carboneous substance on the catalyst known as coking. Comparatively, Co/OPS-AC gave higher conversions of CO₂ and CH₄ as well as higher yields of H₂ and CO as it has a higher surface area than Co/ZSM-5 which subsequently rendered higher activity for the reforming of methane. With the increasing cobalt loadings and reaction temperature, OPS-AC(14) catalyst exhibited improved activity and H₂/CO ratio. Based on these results, cobalt supported OPS activated carbon catalyst was suggested to be more effective for CO₂ and CH₄ conversions.     

竹子生物质废弃物前处理技术比较研究

为开发高效、低成本的预处理技术,促进竹子生物质及其废弃物资源的能源化利用,采用3种不同纤维素预处理方法分别对竹子生物质废弃物——笋壳和竹叶(茎)进行比较研究,同时与玉米秸秆相比较.结果表明,在稀H2SO4–酶解工艺、浓H3PO4–酶解工艺和NaOH–酶解工艺条件下,几种样品水解液中分别存在3、4和5种糖类组分.在稀H2SO4–酶解工艺中,木糖为主要成分,其次为葡萄糖;在浓H3PO4–酶解工艺中,葡萄糖为主要成分,其次为木糖;而在NaOH–酶解工艺,葡萄糖和木糖含量基本相当.同时对样品处理前后的表面结构变化分析表明,不同处理工艺均改变了竹叶(茎)、笋壳和秸秆等样品的表面结构,其结构更为松散,从而有利于纤维素的酶解.     

白果壳遗态Fe/C复合材料对水中磷的吸附特征

为研究PBGC-Fe/C-G（白果壳遗态Fe/C复合材料）对水中磷的吸附特征,以PBGC-Fe/C-G为吸附剂,对吸附剂投加量、溶液体系pH、初始磷质量浓度、温度和吸附剂粒径为影响因素进行静态吸附试验分析,并结合SEM、EDS、XRD和FT-IR等手段对吸附前、后材料进行表征,以揭示PBGC-Fe/C-G的吸附除磷机制.结果表明:①当初始磷质量浓度 < 10 mg/L、吸附剂投加量为0.2 g/（50 mL）、溶液为酸性（pH=3）、反应温度为45℃、吸附剂粒径 < 0.149 mm时,吸附效果最佳,吸附量达1.62 mg/g.②准二级动力学模型和Freundlich吸附等温模型能较好地模拟PBGC-Fe/C-G对磷的吸附过程.③热力学结果显示,ΔG < 0、ΔS>0和ΔH>0,说明PBGC-Fe/C-G对磷的吸附过程是自发、熵增的吸热过程.研究显示,PBGC-Fe/C-G吸附除磷主要通过配位作用、静电引力、等电荷离子交换和物理作用4种协同完成,其中Fe活性位与磷酸根离子的配位反应为主要的反应过程.      

An Investigation of Thermal Decomposition Behavior of Hazelnut Shells

Turkey has a drastic potential in terms of biomass energy and it would be of utmost importance for our energy mix if this huge amount of energy is to be utilized. Thermochemical conversion is the most dominant one among the energy conversion processes. The carbonization process is the key point in determining the kinetic parameters of the fuels utilized. Thereafter, the kinetic parameters obtained from carbonization would be utilized in designing the thermochemical conversion equipments. In this study, the thermal decomposition behavior of hazelnut shells was investigated via dynamical thermogravimetry (TG) under N₂ atmosphere. In order to determine the effects of heating rate and gas flow rate, the experiments were performed in four different heating rates of 5, 20, 50, and 100 K/min and two different nitrogen flow rates of 50 and 100 cm³/min. As the heating rate was increased, peak temperature was increased, maximum temperature shifted to the right (higher T zones) and the maximum rate of weight loss was increased. In addition, lignin decomposition temperature interval was decreased whereas; cellulose decomposition temperature interval was increased. Increasing the heating rate from 5 to 20 K/min, hemicellulose decomposition temperature interval was increased. Total weight loss was slightly increased by the increase of gas flow rate. Kinetic parameters were calculated according to Coats Redfern method. It was found that activation energies of thermal decomposition reactions of hazelnut shell varied between 1.30 and 32.19 kJ/mol.