KMnO_4改性稻壳、稻杆水热炭吸附染料的研究

以稻壳、稻杆为原料,不同浓度KMnO4为水热溶剂,一步完成炭化与改性,并对其进行等电点测定,SEM、FTIR表征。通过静态吸附实验,探究KMnO4改性水热炭对阴、阳离子染料的吸附效果,以及初始染料浓度、样品投加量等的影响。通过吸附等温模型(Langmuir-Freundlich、Langmuir、Freundlich和Temkin)、动力学模型(准一级、准二级和Elovich动力学模型)、吸附机理(颗粒内扩散、Boyd外扩散模型)探究表明,Langmuir-Freundlich、准二级动力学和Elovich模型适合描述吸附过程,膜扩散速率和颗粒内扩散速率共同影响着吸附反应速率。     

KMnO_4改性稻壳、稻杆水热炭吸附染料的研究

以稻壳、稻杆为原料,不同浓度KMnO4为水热溶剂,一步完成炭化与改性,并对其进行等电点测定,SEM、FTIR表征。通过静态吸附实验,探究KMnO4改性水热炭对阴、阳离子染料的吸附效果,以及初始染料浓度、样品投加量等的影响。通过吸附等温模型(Langmuir-Freundlich、Langmuir、Freundlich和Temkin)、动力学模型(准一级、准二级和Elovich动力学模型)、吸附机理(颗粒内扩散、Boyd外扩散模型)探究表明,Langmuir-Freundlich、准二级动力学和Elovich模型适合描述吸附过程,膜扩散速率和颗粒内扩散速率共同影响着吸附反应速率。     

改性椰壳生物炭对水体苯酚吸附效应研究

采用酸碱、MgCl2/FeCl3混合溶液两种方法对椰壳生物炭进行改性,设置不同盐度、温度、pH、瘸殖酸、反应时间等理化条件,研究改性椰壳生物炭吸附苯酚的效应,并进行吸附动力学研究.结果 表明,两种改性椰壳生物炭对水体中苯酚的吸附效果均比未改性好,吸附速率更快.盐度和温度升高均可促进生物炭对水体中苯酚的吸附;pH在2～1...     

原位改性丙酮水热炭对四环素的吸附特性

通过在反应釜中直接添加丙酮制备原位改性丙酮水热炭(XM-AC),并以水热炭(XM)为参照,探究XM-AC对水中盐酸四环素(TCH)的吸附性能。结果表明,相比XM,XM-AC具有较高的比表面积、孔容积和芳香性,准二级动力学和Langmuir更适合描述XM-AC对TCH的吸附过程,表明该吸附过程主要是受两种以上因素共同影响的单分子层吸附。pH值对XM-AC吸附TCH的影响较大。XM-AC对TCH的吸附作用主要为离子交换和π-π电子供体受体相互作用。     

乙酸锌改性稻壳生物炭电容及电吸附Cu2+性能

以稻壳为原料制备生物炭,利用不同浓度的乙酸锌对稻壳炭改性,制得产物分别命名为RHC和MRHC。通过SEM、BET、XRD对制备的生物炭理化特性进行表征。分析表明,改性炭孔隙结构丰富,比表面积较大,且锌以氧化物颗粒状存在于生物炭表面。将改性前后的稻壳生物炭制成电极,测试其电化学性能。结果表明,与未改性生物炭相比,改性后的炭电极比电容大大提高,电阻显著减小,循环性能和倍率性能均有提升。MRHC-0.3（乙酸锌浓度为0.3 mol/L时的改性生物炭）比表面积为495 m2/g,孔容为0.214 cm3/g,该电极在2 A/g下充放电2000次后,其电容保持率为92.16%。将MRHC-0.3电极用于电吸附Cu2+实验,发现在0.9 V,pH为5时吸附效果最好,吸附量为9.57 mg/g。在0.9 V,pH为5,Cu2+初始质量浓度为50 mg/L时,去除率可达63.82%。     

稻壳生物炭对水中萘的吸附特性研究

以稻壳为生物质原料,在管式炉中氮气氛围下分别于300,500,700℃及在马弗炉中限氧500℃下热解制备生物炭(生物炭依次表示为G300、G500、G700和M500),采用批量吸附实验研究四种生物炭对萘的吸附特性,并结合扫描电镜和傅里叶变换红外光谱分析等方法,探讨温度和气氛条件对生物炭吸附萘的影响。结果表明,稻壳生物炭对萘的吸附动力学曲线符合伪二级动力学模型,在24 h内皆达到吸附平衡,平衡吸附量分别为3.299,4.815,4.251,4.756 mg/g,等温吸附曲线可以用Freundlich模型较好地拟合,吸附容量从大到小为G500>M500>G700>G300。4种稻壳生物炭都具有不同程度的管道和表面隆起,管道形状和数量以及表面形态存在较大差异。红外光谱结果有较大的相似性,但是随着温度的升高,—OH、—CH_2、CH_3、C=C和C=O等官能团强度减弱或者逐渐消失,而另外一些官能团如芳烃化合物C—H、C—OH、C—O—C、COO^-等官能团的强度则增加。     

稻壳炭脱硅制活性炭及吸附性能研究

研究稻壳炭脱硅工艺,探究氯化锌法和磷酸法活化脱硅稻壳炭工艺。结果表明,通过热碱溶解回流有很好的脱硅效果。磷酸活化法制备稻壳活性炭相对氯化锌活化法而言,得率较高,在浸渍比为2∶1,浓硫酸添加量为1%,预处理温度240℃,预处理时间1 h,活化温度500℃的实验条件下制得的活性炭,亚甲基蓝吸附值66 mg/g,碘吸附值679 mg/g。实验表明该工艺制得的活性炭不仅吸附性能较好且产量高,在工业应用上具有很好的经济价值。     

酸反应介质下稻壳水热炭对Cu(Ⅱ)、Zn(Ⅱ)的吸附

沼液中Cu²⁺、Zn²⁺等重金属离子浓度高,直接用于灌溉会导致土壤重金属超标,并严重影响农作物的生长。本研究以农作物废料稻壳作为原料,硫酸和磷酸为反应介质,通过水热炭化法制备水热炭,探索了水热温度、酸配比和酸浓度对Cu²⁺、Zn²⁺的吸附性能的影响。结果表明：当以20%稀硫酸和20%稀磷酸两种酸作为反应介质时,改变两种酸的配比在320℃下制备水热炭,当两种酸介质比例为4:2时,对废水中Cu²⁺、Zn²⁺的去除率达到最大,分别为68.54%和27.44%。     

AlCl_3改性柿叶对苯酚废水的生物吸附性能

以柿叶为原料,采用硫酸-甲醛和AlCl_3进行改性制备新型吸附剂硫酸甲醛改性柿叶(SCLAl)。研究了SCL-Al对苯酚的吸附性能,探讨了吸附剂用量、吸附时间、初始浓度、pH值、温度等因素对吸附性能的影响。结果表明:pH值、吸附剂用量和吸附时间对吸附率的影响较明显;温度对吸附率的影响较小;SCL-Al吸附1g/L苯酚时,在pH≥7,1L苯酚溶液中吸附剂用量为15g/L,室温条件下吸附60min基本达平衡,吸附动力学符合准二级动力学方程;吸附行为符合Freundlish吸附等温式。     

改性粉煤灰对苯酚的吸附特性研究

研究了苯酚在改性粉煤灰上的吸附特性。结果表明，改性粉煤灰吸附苯酚速率快，在低pH值下吸附效果更好，等温吸附过程符合Freundlich模型，其吸附等温线为q=1．7081C^0.9248。     

城市污泥与稻壳水热炭混合燃烧特性与动力学

采用热重分析法研究城市污泥、稻壳水热炭及两者不同掺混比的燃烧特性与反应动力学。对比分析其在不同升温速率下从室温升至1000℃的燃烧特性,用Flynn-Wall-Ozawa (FWO)法计算其燃烧过程中的反应动力学参数。结果表明,稻壳水热炭的挥发性、着火和燃尽指数均高于城市污泥,具有较好的燃烧特性,掺混稻壳水热炭使城市污泥混合燃烧时发生热滞后现象。随着稻壳水热炭掺混比的增加,共混物的燃烧残余质量减少,着火性能变差,燃烧性能变强。活化能的相关系数均高于0.95,稻壳水热炭掺混高于50wt%时,共混物的平均活化能低于稻壳水热炭单独燃烧的平均活化能,掺混70wt%稻壳水热炭时出现最低平均活化能,为85.48 kJ/mol。城市污泥与稻壳水热炭混燃时有协同交互作用,且掺混50wt%稻壳水热炭时效果最佳。     

Competitive adsorption of phenol and resorcinol onto rice husk ash

The present study deals with the adsorptive removal of phenol and resorcinol from aqueous solution onto rice husk ash. The competitive adsorption equilibrium of the binary mixtures (phenol/resorcinol) was determined by conducting batch experiments with initial concentration varying in the range of 50 to 1000 mg/L. In order to evaluate multicomponent adsorption isotherm parameters, individual adsorption equilibrium studies were also carried out. Langmuir, Freundlich and Redlich-Peterson equilibrium isotherm models were used for single compound equilibrium sorption data modeling. All three models almost similar fit for single compound equilibrium data. Binary equilibrium adsorption data and the parameter evaluated from single adsorption data were fitted to various multicomponent isotherm models by minimizing the sum of square of error. The extended Langmuir model gave the better fit to the experimental adsorption data of phenol and resorcinol from binary systems onto rice husk ash. It seems that both phenol and resorcinol compete for the same adsorption sites on rice husk ash. The net interactive effect of phenol and resorcinol on the adsorption of resorcinol by rice husk ash was found to be antagonistic.     

阳-非离子有机膨润土对水中苯酚的吸附作用

用阳、非离子表面活性剂修饰膨润土,制得有机膨润土,研究了阳-非离子有机膨润土对水中苯酚的吸附性能及修饰剂用量、温度和pH值对其的影响,并探讨了吸附机理。结果表明,有机土样对苯酚的吸附等温曲线是线性曲线,吸附主要为分配作用,吸附作用的大小由有机膨润土中有机碳的含量决定,膨润土有机碳对有机物的溶解起了增溶作用,有机碳含量高的膨润土对水中苯酚的吸附能力增强;对苯酚的吸附量随温度、pH的升高而降低。     

阳-非离子有机膨润土对水中苯酚的吸附作用

用阳、非离子表面活性剂修饰膨润土,制得有机膨润土,研究了阳-非离子有机膨润土对水中苯酚的吸附性能及修饰剂用量、温度和pH值对其的影响,并探讨了吸附机理。结果表明,有机土样对苯酚的吸附等温曲线是线性曲线,吸附主要为分配作用,吸附作用的大小由有机膨润土中有机碳的含量决定,膨润土有机碳对有机物的溶解起了增溶作用,有机碳含量高的膨润土对水中苯酚的吸附能力增强;对苯酚的吸附量随温度、pH的升高而降低。     

Chromium modified silica from rice husk as an oxidative catalyst

RH-Cr and RH-Cr500 were synthesized from rice husk by solvent extraction and gel precipitation technique. The specific surface area of RH-Cr and RH-Cr500 were found to be 0.542 and 1.20 m² g⁻¹ respectively. Energy dispersive X-ray (EDX) analysis showed that Cr(III) was homogenously incorporated in the matrix of both samples to a maximum of ca. 16% in RH-Cr500. Elemental analysis showed that RH-Cr contained ca. 15% carbon, while RH-Cr500 contained negligible amounts. FTIR analysis showed the extracted solid contained silanol (Si–OH) and siloxane (Si–O–Si) groups. Catalytic oxidation of cyclohexane with H₂O₂ using RH-Cr as the catalyst showed a 27.13% conversion to cyclohexanone and cyclohexanol with a selectivity of 57.37% and 42.63% respectively. However, RH-Cr500 showed only 14.01% conversion but with a selectivity of 64.83% of cyclohexanone and 35.17% of cyclohexanol. Epoxidation of cyclohexene using H₂O₂ with RH-Cr as the catalyst gave a conversion rate of 30.17% with a selectivity of 11.51% towards cyclohexene oxide, 63.21% 2-cyclohexen-1-one and 25.29% 2-cyclohexen-1-ol. The same reaction with RH-Cr500 as the catalyst showed 21.28% conversion with 14.65% cyclohexene oxide, 68.71% 2-cyclohexen-1-one and 16.64% 2-cyclohexen-1-ol. In the catalytic oxidation of cyclohexanol to cyclohexanone, RH-Cr showed a conversion of 12.25% while RH-Cr500 showed a conversion of 13.52%. No others products were detected in the conversion. Comparison with published catalytic systems showed that RH-Cr and RH-Cr500 to be a better catalyst even though the surface area of these catalysts were low.     

Silver modified porous silica from rice husk and its catalytic potential

Rice husk silica modified with Ag (RH-Ag) and its calcined form, RH-Ag(C) are heterogeneous catalysts prepared from rice husk. The sodium silicate was extracted from rice husk using a simple solvent extraction technique. Silver was added during the precipitation of the gel to form RH-Ag. Calcination of RH-Ag yielded RH-Ag(C). RH-Ag and RH-Ag(C) was found to have a well defined amorphous phase and a crystalline phase. TEM analysis showed that silver was encapsulated into the silica matrix. Well defined mesoporous channels were found in RH-Ag(C). The EDX analysis showed that silver was indeed incorporated in the matrix of RH-Ag but it was not homogenously distributed. The specific surface area of RH-Ag and RH-Ag(C) was found to be 447 and 419 m² g⁻¹ respectively. The cation exchange capacity (CEC) for RH-Ag was found to be 0.470 mmol g⁻¹ which was higher than that of RH-Ag(C) with 0.273 mmol g⁻¹. Both the CEC and the BET values for RH-Ag(C) was consistent with the calcination process. Catalysis of benzyl alcohol using RH-Ag and RH-Ag(C) gave two products which were identified as benzaldehyde and dibenzyl ether. Percentage conversion was higher when the reaction was conducted with pure oxygen (14.0%) than in open air (0.60%). Overall, RH-Ag(C) was found to be a better catalyst for the formation of dibenzyl ether. The optimum weight and time of reaction for the oxidation was found to be 0.3 g and 3 h respectively for both catalysts. It was found that even in an inert atmosphere, 13% of benzaldehyde was obtained with RH-Ag(C) as catalyst. Mechanisms for the formation of benzaldehyde under oxygen and inert atmosphere and the condensation mechanism assisted by the presence of the Ag on the surface of the catalyst have been suggested.     

改性膨润土对苯胺与苯酚混合液的吸附性能

研究酸活化膨润土和有机改性膨润土对苯胺和苯酚混合溶液的吸附性能,结果表明,酸活化膨润土对苯胺的吸附效果明显优于苯酚,具有较强的吸附选择性;有机膨润土对苯胺和苯酚的吸附无明显差别。吸附动力学研究表明,酸活化膨润土与有机改性膨润土对苯胺的吸附均符合准二级吸附动力学模型,相关系数分别为R²=0.999 8和R²=0.997 9。酸活化膨润土对苯胺的吸附符合Freundlich等温线模型,有机膨润土对苯胺的吸附数据对Freundlich等温线模型与Langmuir等温线模型均有较好的拟合。