A high Li-ion diffusion kinetics in multidimensional and compact-structured electrodes via vacuum filtration casting

Manufacturing process,diffusion co-efficient and areal capacity are the three main criteria for regulating thick electrodes for lithium-ion batteries(LIBs).However,simultaneously regulating these criteria for LIBs is desirable but remains a significant challenge.In this work,niobium pentoxide(Nb_(2)O_(5))anode and lithium iron phosphate(LiFePO_(4))cathode materials were chosen as the model materials and demonstrate that these three parameters can be simultaneously modulated by incorporation of micro-carbon fibers(MCF)and carbon nanotubes(CNT)with both Nb_(2)O_(5) and LFP via vacuum filtration approach.Both as-prepared MNC-20 anode and MLC-20 cathode achieves high reversible areal capacity of≈5.4 m A h cm^(-2)@0.1 C and outstanding Li-ion diffusion coefficients of≈10~(-8)cm~2 s~(-1)in the half-cell configuration.The assembled MNC-20‖MLC-20 full cell LIB delivers maximum energy and power densities of244.04 W h kg^(-1)and 108.86 W kg^(-1),respectively.The excellent electrochemical properties of the asprepared thick electrodes can be attributed to the highly conductive,mechanical compactness and multidimensional mutual effects of the MCF,CNT and active materials that facilitates rapid Li-ion diffusion kinetics.Furthermore,electrochemical impedance spectroscopy(EIS),symmetric cells analysis,and insitu Raman techniques clearly validates the enhanced Li-ion diffusion kinetics in the present architecture.

Experimental investigation of oil particles filtration on carbon nanotubes composite filter

Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.

Affordable Water Filtration Technology for Disinfection By-Product Control for Small Rural Communities by Using Carbon Extracted from Local Fly Ash

The fly ash generated from local pulp and paper industries was transformed into activated carbon (AC) through physical activation process in a high temperature tube furnace in this study. Effects of two factors including activation temperature and activation time were investigated. Iodine number (IN), methylene blue value (MBV), and surface microstructure were all analyzed to assess the adsorption capacity of different carbon samples. The surface area of the carbon sample increased significantly from 486.44 m2/g to 847.26 m2/g before and after activation. The jar tests revealed that the use of 0.5 g (AC)/L (water) has the highest adsorption effectiveness. Meanwhile, the column filtration experiment indicated more than 60% of the organic matter can be removed by the carbon barrier within 2 hours filtration. The follow-up chlorination experiment illustrated that the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) could be considerably prevented after filtration. Above all, the cost-effective carbon filtration technology developed in this study can potentially be applied as a pre-treatment technology for intake source waters for local communities.

Ensuring water security by utilizing roof-harvested rainwater and lake water treated with a low-cost integrated adsorption-filtration system

Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.

DUAL FILTRATION EFFECT OF GEOCHEMICAL AND BIOGEOCHEMICAL PROCESSES IN THE CHANGJIANG ESTUARY

Dissolved nutrients (NO3- , PO4 3- , SiO32- ) and oxygen , chlorophyll- a , pH and Eh were measured on board during a cruise in August 1988 in the Changjiang Estuary region . Heavy metals , organic matter and carbonate contents were analyzed in laboratory. The results show that geochemical processes in the Changjiang Estuary have dual filtration effect: on the one hand geochemical filtration effect, reflected by ferromanganese oxide flocculation and sedimentation , occurs near the turbidity maximum, and leads to enrichment of heavy metals in suspended matter and sedi -ments; on the other hand biogeochemical filtration , reflected by nutrients consumption , organic matter and carbonate sedimentation and enrichment of trace elements in suspended matter. occurs outside the plume water front. The biogeochemical filtration affects the environmental conditions ; the dissolved oxygen and pH increase in surface water and decrease in bottom water. The biogeochemical filtration effect outside the plume front is

Study on enhanced filtration for the 2-methylisoborneol removal in drinking water treatment processes

Pilot plant studies on 2-methylisoborneol(2-MIB)removal in drinking water by biological activated carbon-sand filter(BACSF)were conducted in this paper.The biological activated carbon was chosen from a BAC filter of an advanced treatment plant which has operated for 1 year.The results showed that the BACSF worked effectively when high concentrations of MIB in raw water especially in summer season.Most of the MIB was removed within 450 mm of the top packed media and the removal rate was 75.24%.The biomass on the surface of activated carbon increased to 103 nmolP/g carbon in August.In addition to MIB,turbidity,UV254 and DOC consumption value are also effectively removed by BACSF.The micro flocculation in combination with BACSF enhanced filtration test provided the evidence that the micro-flocculation made the contaminant in water forming the colloidal matter and it improved the BACSF removal ability of MIB.The optimum PACl dosage was 0.2 mg/L and the PACl contact time was 2-4 min.

Effects of Temperature on the Preparation of Magnesium Carbonate Hydrates by Reaction of MgCI2 with Na2CO3

Homogeneous(unseeded)precipitation of magnesium carbonate hydrates by the reaction of MgCl2 with Na2CO3 in supersaturated solutions between 273 and 363K was investigated.The compositions,morphologies and filtration characteristics of the precipitates were studied in detail.The magnesium carbonate hydrates obtained at 313K and in the range of 343-363K showed good morphologies and filtration characteristics.Magnesium oxides(MgO)with high purity(97.6%-99.4%)were obtained by calcining magnesium carbonate hydrates at 1073K.

Processes for the Clarification of the Crude Oil of Baobab Seeds Extracted by Pressing on Activated Carbon Elaborated from the Capsules of the Fruit (Adansonia digitata L.)

The baobab, Adansonia digitata L. plays an important role in the economy of local populations. The oil from the seeds of the baobab fruit is nowadays highly prized because of its numerous cosmetic and therapeutic applications and its composition of unsaturated fatty acids, sterols and tocopherols. However, unlike refined oils, locally extracted baobab oil has not undergone purification operations to ensure its quality. Only a filtration on special cloths is carried out after decantation. Indeed, the oil obtained after pressing is cloudy because of the presence of various impurities. It therefore requires treatment operations to make it more attractive and of higher quality. Therefore, in order to provide innovative solutions to local companies to improve the quality of vegetable oils, a study of clarification (treatment) of crude oil is necessary. An experimental device has been developed in the laboratory. It includes a glass column and a filter bed of dune sand and activated carbon. This study has shown the efficiency of the experimental device. Indeed, the activated carbon, thanks to its adsorbing power, has allowed a significant decrease in turbidity at the 5% threshold, from 14.61 NTU for the raw oil to 0.08 NTU for the oil filtered on 3% carbon and 0.033 NTU for the oil filtered on 5% carbon. That is to say an abatement higher than 95%. This decrease in turbidity could be correlated with the decrease in brown index from 187.39a for the initial crude oil to 128.53d for the oil treated with 3% activated carbon versus 187.59a for the oil filtered on cloths. The lowest brown index was observed with the filtration using 5% activated carbon (35.99b). Thus, for the yellowness index, only the filtration on 5% charcoal allowed to obtain a significant decrease in yellowness. The yellowing index of the oil with 5% was 44.67b against 79.04a for the oil filtered with 3% activated carbon, 86.33a for the crude oil and 86.46a for the oil filtered on cloths. Finally, the oil sample treated with 5% activated carbon had the clearest clarity than the other samples with a clarity (L) equal to 97.98c against 95.63d for the oil treated with 3% carbon and 94.99b for the oil filtered on filter cloths. According to the results obtained, the experimental device made it possible to obtain a clearer baobab oil with a low brown index, thus improving the sensory quality of the oil.

三种不同过滤方式对特香型白酒质量的影响研究

从白酒的气相色谱成分、离子色谱成分、感官评定等方面研究分析活性炭吸附过滤、冷冻过滤、聚能量膜过滤对特香型白酒的影响。结果表明:活性炭吸附过滤对酒体骨架成分及风味影响较大、净化能力较强,适用于过滤风味欠佳的酒体;冷冻过滤对酒体骨架成分及风味影响较小,适用于过滤风味一般的酒体;聚能量膜过滤对酒体骨架成分及风味基本无影响、滤后酒体的自然微黄颜色及风味可以最大程度地得以保留,适用于过滤风味较好的酒体。

臭氧-CNTs预沉积耦合方法缓解膜污染研究

以腐殖酸(humic acid,HA)和海藻酸钠(sodium alginate,SA)作为模型污染物,考察了臭氧预氧化和碳纳米管(carbon nanotubes,CNTs)预沉积联合技术对膜污染形成过程和形成规律的影响。通过测定HA和SA物化特性的变化,结合膜滤过程中比通量变化,辅以Hermia模型和传统滤饼过滤模型,分析了臭氧预氧化和CNTs预沉积缓解膜污染的机理。结果表明,经臭氧氧化后,HA和SA的电负性和亲水性增强,且由于发生微絮凝作用,粒径增大。臭氧预氧化对于HA造成的膜污染无明显改善作用,当氧化后HA粒径接近基膜孔径时,膜孔被完全堵塞甚至加重膜污染;臭氧破坏了SA的凝胶特性,大幅缓解了膜表面的滤饼层污染。不同孔径的基膜进行CNTs预沉积后,表面CNTs层可以拦截吸附部分HA和SA分子,从而缓解了HA和SA造成的膜污染。0.45μm PVDF基膜孔径与CNTs层的孔径相差最大,经CNTs预沉积后,在膜表面形成一层致密的过滤层,缓解膜污染的幅度最大。臭氧预氧化与CNTs预沉积联用后,在CNTs沉积量较高的情况下能够缓解HA造成的膜污染,对SA造成的膜污染也起到明显缓解作用,在有效降低膜表面滤饼形成的同时,能够延长膜孔堵塞时间或增加膜孔堵塞到滤饼的过渡阶段时间。

碳酸盐岩酸压裂缝内净压力变化规律研究

酸化压裂是开发碳酸盐岩储层最常用的增产技术,而酸压裂缝内净压力是反映裂缝扩展特征、推断裂缝几何形态的重要参数。以水力压裂裂缝延伸机理为基础,基于酸岩反应理论,考虑酸岩反应导致的缝宽变化、CO_(2)气体膨胀、酸液滤失及岩石力学性质变化,结合PKN模型,建立酸压裂缝内的净压力计算模型并进行验证。研究分析酸压裂缝内净压力的影响因素及其规律,结果表明:距缝口距离越远,水力裂缝与酸压裂缝的缝宽均越小,酸液的溶蚀作用会使裂缝宽度增大。随着液体的滤失,离缝口越远液体越少,水力裂缝与酸压裂缝净压力逐渐减小,越靠近裂缝尖端净压力衰减越快。随着作用时间延长,酸压裂缝缝宽逐渐增大,前期随着大量CO_(2)生成,净压力迅速增大,随着酸液消耗与滤失增加,之后逐渐减小并趋于稳定。随着排量的增大,滤失增大,酸压裂缝缝宽及净压力均逐渐增大且增量越来越小。在黏度较小的情况下,滤失较大,净压力逐渐减小;在黏度较大的情况下,CO_(2)膨胀作用大于滤失作用,净压力逐渐增大。随着酸液浓度的增大,酸岩反应速率增大,反应生成CO_(2)增多,净压力逐渐增大。

绿色荧光碳点的合成及其在铁离子检测中的应用

以还原型谷胱甘肽为碳源,丙烯酸异辛酯为溶剂通过溶剂热法制备了具有绿色荧光发射的氮硫共掺杂碳点(G-CDs)。所制备的碳点在水中分散性良好,尺寸为(5.17±0.23)nm。在398 nm的激发波长下,其发射波长为517 nm,荧光量子产率为13.2%,且具有激发独立性。因为Fe 3+与G-CDs之间存在特异性内滤效应和电子转移,可以有效淬灭G-CDs的荧光。基于此类性能,我们开发了一种新的Fe 3+荧光检测方法,线性范围为20~80μmol/L,检测限为8.16μmol/L。在实际样品检测中,G-CDs具有良好的灵敏度,在荧光探针领域具有应用潜力。

一种生物活性炭的制备及其对BTEX去除效果研究

针对BTEX污染问题,在传统活性炭吸附技术的基础上,设计了一种依托特殊微生物的,能够进行原位再生的生物活性炭并对其处理效率进行研究。从被苯系化合物污染的土壤样本中提取了微生物样品,经过筛选训化后保留了3株菌种B-01、B-02、B-03。利用生物滴滤法将微生物固定在椰壳活性碳上制成生物活性碳(BAC),通过人工模拟的BTEX废气研究BAC再生效应对于处理BTEX废气的作用。研究结果表明,3株菌种分别为芽孢杆菌(Bacillus)、芽孢杆菌(Bacillus)和假单胞菌(Pseudomonas),最适反应温度为30℃,通过持续喷淋营养液,活性碳上挂载的菌种能够在35 d内保持活性。所制备的BAC对乙苯的吸附能力最强,乙苯去除率可达98.75%。BAC在低负载情况下BTEX去除率最高可达98%。通过微生物挂膜延长了活性炭的使用寿命,为降低石油加工废气处理成本提供了技术支持,具有良好的实用价值。

活性炭联合正弦波电场促进污泥脱水

利用活性炭联合正弦波电场促进污泥脱水,通过对泥饼电流、温度及泥饼、滤液的性质分析探究活性炭对污泥脱水的促进机理。结果表明,活性炭可以提升污泥导电性,增强污泥中的电化学反应,从而降低了泥饼含水率。在占空比为100%,投加量为5%污泥干重时,泥饼含水率为43%;活性炭可以吸附滤液中有机物组分,相比未投加,投加5%活性炭的总有机碳值降低了1.708g/L,降低了滤液处理成本。

基于水相剥离的单壁碳纳米管薄膜透光和导电特性

高性能透明导电薄膜是光伏电池、平板显示器等光电子器件的重要组成部件。发展了基于水相剥离的单壁碳纳米管透光导电薄膜制备方法,分析单壁碳纳米管薄膜透光率、方阻和浓度之间的依变关系,探究杂化处理对薄膜透光和导电性能的影响规律。结果表明:通过调节单壁碳纳米管浓度实现了薄膜在太阳光谱范围(300~2500 nm)透光率(50%~96%)的准确预测、方阻特性在3~100Ω·sq^(-1)之间的精准调控;通过酸回流和强氧化的纯化过程,透光率在750~2000 nm波段平均提升3.1%,方阻降低50%以上。该透明导电薄膜具有高透光率和低电阻的优异综合性能,在光电子器件设计方面具有广阔的应用前景。

生化—电催化氧化—炭吸附工艺处理水基泥浆压滤液

采用生化—电催化氧化—炭吸附组合工艺处理钻井水基泥浆压滤液。以COD为主要指标、其他污染物为辅助指标,考察去除效果,采用GC-MS和FTIR分析有机物的去除历程,XRF分析元素变化。表征结果显示,组合工艺可去除大部分有机物,顺-7-十四碳乙酸酯、3-氨基-6-甲基吡啶-2(1H)-酮和2-癸基噻吩是本工艺难去除的有机物。实验结果表明:水基泥浆压滤液经组合工艺处理后,出水COD小于50 mg/L,各项指标均可达到辽宁省《污水综合排放标准》(DB 21/1627—2008);经组合工艺处理后,压滤液中Ca、C、Cl、S、O元素含量降低。

Impact of carbon-based nutrient enhancement on biofiltration performance for drinking water treatment

Incorporation of a carbon-based nutrient enhancementstrategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids(including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon(DOC) in the source water, including disinfection by-product(DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate(ATP), dissolved oxygen(DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss,turbidity, p H, DOC, UV254, and DBP formation potential(DBP FP). The introduction of carbonbased nutrients significantly increased biomass activity, where ATP values peaked at 976 ng/g of filter media, 853 ng/g, and 513 ng/g for amino acids, inulin, and sucrose-spiked biofilters,respectively, while a non-spiked control only reached 104 ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters(R^2> 0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated(p > 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal(DOC and UV254) or DBP FP when treated filters were compared to a control.

催化裂化油浆固含量测定方法研究进展

催化裂化油浆是催化裂化装置的副产品,油浆固含量的高低直接影响油浆的高附加值利用及催化裂化装置的安全平稳运行。因此,油浆固含量的准确快速测定对其综合利用及生产监测均具有重要作用。目前,油浆固含量的测定尚无统一的权威标准。介绍了油浆固含量的几种主要测定方法,包括传统离心法、新型离心法、灰分法、炭化灼烧法、传统过滤法、滤膜抽滤法、显微镜法等,并通过对比每种方法的优劣,分析其适用的范围,为油浆脱固效率的考察及炼油厂催化裂化装置的安全平稳运行监测提供支持。滤膜抽滤法能够全面地反映固含物的组成成分,不受油浆性质限制,准确度高,且用时较短,可应用范围非常广泛;更重要的是,滤膜抽滤法还适用于脱固后油浆固含量的测定,能够较为真实地反映出油浆的脱固效果。

Improved electrical resistance-pressure strain sensitivity of carbon nanotube network/polydimethylsiloxane composite using filtration and transfer process

The electrical resistance-pressure strain sensitivity of carbon nanotube network (NTN)/polymer composite is investigated. In this research, polydimethylsiloxane (PDMS) is used as the polymer matrix. The composite of NTN embedded in PDMS matrix has been fabricated by using filtration and transfer process. The thickness of NTN/PDMS composite can be controlled. Electrical re- sistance and pressure strain of the NTN/PDMS composite are measured simultaneously. Electrical resistance of NTN/PDMS composite has been obtained as a function of pressure strain. The NTN/PDMS composite exhibits linear change in electrical re- sistance as a result of pressure strain and has improved electrical resistance-pressure strain sensitivity. The NTN/PDMS composite has 90.6% resistance change at 6% pressure strain. The electrical resistance-pressure strain sensitivity of NTN/PDMS composite using filtration and transfer process is 2.13 times of the traditional NTN/PDMS composite. The characteristic in electrical resis- tance change implies that NTN/PDMS composite can be used as pressure strain sensors and applied to sensor systems.

甘蔗原汁制备转化糖浆前处理工艺研究

以甘蔗原汁为原料,通过微/超滤、活性炭吸附及离子交换树脂吸附依次处理甘蔗原汁,以蔗汁色值、混浊度及电导灰分为考察指标,通过单因素试验、正交试验优化处理工艺。结果表明:最佳过滤孔径为0.05μm;活性炭吸附最佳工艺条件为活性炭添加量0.5%(以微/超滤处理后的蔗汁质量为基准)、吸附温度90℃、吸附时间20 min、pH 5.0。离子交换树脂吸附最佳工艺条件为糖液与树脂质量比1∶1、吸附温度70℃、吸附时间60 min、pH 5.0,在此工艺条件下,所得蔗汁色值为(26±6)IU,混浊度为(16±6)MAU,电导灰分为3.29%±0.034%,蔗汁品质佳。