Water quality should be supervised in whole process from the source to the tap, which is an important step to govern water pollutions. However, the available detection device are always large equipment with some drawbacks, such as single measurement parameter, complicated structure, large size, and high price, which make them cannot meet the practical demands. Therefore, it is meaningful to develop integrated water detection sensor and system which are multiparametric, simply structured, miniature, low power consumed, and low cost. Aiming at the field and in-site monitoring for water quality, this study developed a multiparametric integrated micro-sensor and a portable detection device to measure pH, conductivity, and temperature in water. The developed sensor has some advantages, such as miniature size, low cost and power consumption, high sensitivity and stability. Meanwhile, the developed detection device is capable of detecting multiple water quality quickly, conveniently, and sensitively in filed. A multiparametric integrated micro-sensing chip, consisting of pH working electrode, solid-state reference electrode, conductivity sensor, and temperature sensor, was fabricated with micro-electro-mechanical system (MEMS) technique. The pH sensing electrode was modified with hydrous iridium oxide (IrOx) film prepared by electrochemical deposition technique, which exhibited super-Nernstian response. The four-terminal conductivity sensor configured with concentric rings prevent the errors caused by double electrical layer and proximity effect. The Pt thin-film temperature sensor could be used to compensate the thermal error of pH and conductivity measurements in the future. The characterization results showed that the developed pH sensor exhibits a sensitivity of 67.60mV/pH in the detecting range of pH2.22 to pH11.81, with fast response (response time is shorter than 6s); the on-chip micro-solid-state refer
Methane rich fluids are a widely observed phenomenon in cold-seep and gas hydrate-bearing region. Geochemistry of such fluids records the cold-seep activity, hydrate status and biogeochemical processes, e.g. organoclastic sulfate reduction (OSR) and anaerobic oxidation of methane (AOM), and is considered as an important method to understand the cold-seep and gas-hydrate systems. Pore water samples collected from gas hydrate-drilling regions in the Dongsha Area (D17-15; D08-13) and Shenhu Area (SH-W01; SH-W02) of the South China Sea by gravity piston cores were measured for geochemical parameters of major constituents (SO42?、Cl-、PO43-、Na+、K+、Ca2+、Mg2+), trace elements (Sr2+、Ba2+), dissolved inorganic carbon (DIC), and δ13CDIC values in this study. The one-dimensional reactive transport model(RTM) was applied to the pore water parameters to determine the migration process and reaction rate of methane in shallow sediments, to calculate fluxes of upward methane, and to provide clues for assessing the potential resource in the gas hydrate-drilling regions of South China Sea. Pore water geochemical results from sites D17-15 and D08-13 in hydrate-drilling area in the Dongsha Area showed that sulfate reduction is driven by different biogeochemical processes during early diagenetic processes. The sulfate-methane interface (SMI) is about 6.6 m below the seafloor. Shallow depth of SMI, nearly linear sulfate consumption-depth profile, a sudden increase of Ba2+ concentrations below the SMI, and highly negative δ13CDIC values (-38.8‰) at site D17-15 revealed intense AOM. Site Concentrations of Mg2+, Ca2+and DIC and δ13CDIC values and no obvious change in the sulfate consumption-depth profile at site D08-13 indicated that the main sulfate reduction biogeochemical process was OSR. Based on the numerical simulation results, the diffusion fluxes at sites D17-15 and D08-13 of downward total sulfate are 35.3 mmol m-2yr-1 and 16.6 mmol m-2yr-1, and the diffusion fluxes of
Nanoparticles (NPs) have outstanding physicochemical properties such as optical, electronic, magnetic, and other properties which make them ideal candidates for applications in various fields, including industrial and consumer products. Due to their extensive consumption, the NPs would inevitably enter into the environment during manufacturing, use, disposal and recycling, which simultaneously trigger concerns on their risks to the environmental safety and human health. Once released into the environment, NPs will transport and redistribute in aquatic, atmospheric, soil and other environmental systems. In addition, they will undergo different physical and chemical transformations, which may be influenced by the environmental factors and their physicochemical properties, imposing impact onto their transport, transformation and bioavailability. However, previous researches on the environmental behavior and process were mainly focused on the normal environmental media such as the aquatic system, and studies on the behavior and effects of NPs at the environment interface are very scarce at present.This dissertation focuses on investigating the processes and effects of transport and transformation of nanomaterials (NMs) in the environmental water interface. By using the inductively coupled plasma mass spectrometry (ICP-MS) for quantification, and laser Raman spectroscopy (Raman), ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy/high resolution transmission electron microscopy (TEM/HRTEM) and dynamic light scattering (DLS) for qualitative analysis and characterization of NMs, we expand the research works on environmental behaviors from the bulk water to the water interface (i.e., water surface microlayer and ice liquid interface). We hope that this study is beneficial to gain more comprehensive and deep understanding about the transport, transformation, and fate of NMs in various environment media.In the first part, the applications, category an
Diols, including ethylene glycol (EG) and propylene glycol (PG), are important raw materials and intermediates in chemical industry. As the most concerned and simplest diol, EG becomes the second major derivative of ethylene. China is the largest consumer of EG. The traditional technology has some disadvantages, such as large water ratio (H2O/EO), high energy consumption and low EG yields. Under the pressure of energy crisis and high demand, technological innovation has become an inevitable trend. There are two most promising alternative processes, including CO2 based process via ethylene carbonate (EC) and catalytic hydration process of ethylene oxide (EO). All the two new technologies become international research frontiers, of which the most important is catalyst development. To overcome the disadvantages of current catalysts, including uncombined activity and stability of carbonylation catalysts in EC process, as well as scarce activity and selectivity of EO hydration catalysts, new catalysts would be designed by combining the feature of ionic liquids and porous materials. With the good activity and clustering effect, ionic liquids could be used to modify and assemble with stable porous materials to function synergistically in efficient catalytic synthesis of EG. In this work, investigations were conducted around three aspects, including ionic liquids adjusting methods on formation and assembly of porous materials, the structure-activity relationship between composite materials and catalytic performance, and synergistic catalytic mechanisms by ionic liquids and materials. The study will open a new approach for development of highly efficient catalysts in EG synthesis process and provide the basis for catalyst development of other diols. The innovative achievements of the thesis are as follows:(1) Ionic liquids were used as both templates and dopants for the preparation of carbon nitrides for epoxides carbonylation. Based on characterization and catalytic evaluat
Nowadays, chemical industry was already the key basis of social development, but it depended much on the traditional fossil resource such as the oil, coal and natgas. Moreover, due to the non-biodegradable property of fossil resource, most synthetics made by it were the source of environmental pollution. Thus, increasing consumption and pollution pressure have led to increasing policy mandates to seek alternative and renewable carbon resources. Where, biomass resource obtained unprecedented attention as the only renwalbe carbon resource, which was considered as the best alternative choice. Especially biomass polyol, the transformation technique of polyol into fuel was high compatible with that of fossil indusitry. Biomass feedstocks are highly functionalized and water soluble because of the high oxygen content. The conversion of carbohydrate into hydrocarbon involves selective removal of oxygen from the biomass. Thus, aqueous-phase process (APP) was a promising route for the transformation of biomass polyol into value-added products in biomass industry. However, APP, as a catalytic process, its research history was very short, and the mechanism of removal of oxygenates from water-soluble feedstocks was complex in different catalytic system. Moreover, some of the challenges of APP are follows: design of active and stable catalysts, synergistic effect between metal/acid catalytic acitivities, porous-structure control for target products, and products that fit into the existing liquid transportation fuel or commodity chemical infrastructure.In this paper, various porous materials were investigated for sorbitol hydrodeoxygenation (HDO) reaction to screen the stable catalysts with high performances. Firstly, zeolite materials with different pore sizes were selected. Where, physically mixed catalysts Ni-HZSM-5/SG and Ni-HZSM-5/SBA-15 were made by mixing the micropore zeolite (ZSM-5) with caropore silica gel (SG) and mesoporous SBA-15, respectively. The results indicated that the obtained oil products of these catalysts’ experinments were gasoline range components with high octane number, inculding long-chain alkanes, aromatics, cyclic-hydrocarbons etc. Thus, lots of characterization analyses and contrast experiments were carried out for the mechanism study. Secondly, porous carbon catalysts (Ru/C+H3PO4, RuMo/C, RuMo/C-P, etc.) were applied for sorbitol conversion with high C5/C6 alkane gasoline range products. In order to study the catalytic mechanism in hydrodeoxygenation reactions, a series of pre- and post-characterization analyses (N2-adsorption, Bohem titration, ICP, SEM, TEM, TG, XRD, Raman, XPS, FTIR, H2-TPR, CO-TPD, NH3-TPD and Py-IR, etc.) and detailed studies of contrast experiments were performed over relevant catalysts.In chapter 1, the introduction of biomass polyol into bio-gasoline was presented, including gasoline properties, bio-gasoline transformation path, polyol hydrodeoxygeantion process, etc. In chapter 2, detailed experimental materials, operation procedures, methods of measurements and characterizations were presented.In chapter 3, systematic studies were carried out to investigate one-pot aqueous phase catalytic conversion of sorbitol to gasoline range products (C5-C12 alkanes) over bifunctional Ni-based catalysts as the carbon chain extension and hydrodeoxygenation steps played critical roles in the high-energy-density hydrocarbons production. Characterization study indicated the textural properties, phase compositions, acid behavior and morphologies of the catalysts. The catalytic performances were tested in a fixed bed reactor. Contrast experiments of HZSM-5, Ni-HZSM-5 and Ni-HZSM-5/SG indicated the synergistic effect of metal/acid activities in the HDO reaction. It was found that the physically mixed Ni-HZSM-5/SG catalyst realized the carbon chain extension and exhibited excellent performances on HDO reaction with 46.9 % of gasoline (C5-C12) yield and 45.5 % of C7-C12 hydrocarbons. The oil product was promising for bio-gasoline as the high heat value. In addition, the effect of pore diameter of SG on product distribution was also discussed in the paper. The results indicated the smaller pore diameter, the lower oil yield. In a word, it provided a novel transformation of sorbitol into long-chain alkanes by one-pot process over the bifunctional catalyst (Ni-HZSM-5/SG), wherein hydrodeoxygenation, ketonization and aldol condensation steps were integrated.In chapter 4, renewable liquid fuel with high content of aromatics and cyclic-hydrocarbons was obtained by aqueous catalytic conversion of biomass sorbitol over Ni-HZSM-5/SBA-15 catalyst. Aromatics and cyclic-hydrocarbons were the significant components of bio-gasoline with high energy-density. However, conventional technologies on bio-fuel production could not produce these products without further aromatization and isomerization. Texture characteristics of the catalyst were determined by N2-adsorption, indicating the bimodal pore structures of catalysts with micropore (HZSM-5, average pore width: 0.56 nm) and mesoporous (SBA-15, average pore width: 5 nm). Moreover, the NH3-TPD and Py-IR analyses confirmed the surface acid sites on the catalysts, including weak and strong acid sites, and predominantly Lewis type. To study the reaction mechanism, contrast experiments were carried out over different catalysts (HZSM-5, Ni-HZSM-5, Ni/SBA-15 and Ni-HZSM-5/SBA-15).In chapter 5, the mechanism of polyol hydrodeoxygenation into C5/C6 alkane over Ru/C+H3PO4 catalytic system was investigated in trickle-bed reactor. The performance of hydrodeoxygenation reaction and products distribution with the time-on-stream (TOS) suggested that the C-C cracking property was gradually suppressed with more long-chain alkanes in the products. In-situ analysis of Ru/C+H3PO4 aqueous catalytic system would be challenging at present, but the detailed studies of series catalysts and HDO performance gave some indication. That was the spent catalyst (Ru/C-spent) presented more acidic sites and lower C-C cracking property than that of fresh catalyst, which might be due to the influence of adsorbed phosphate additives. To further study the influence mechanism, phosphated ruthenium catalysts were prepared and carried out in neutral sorbitol solution, and experiments of HDO reaction over Ru/C with different mineral acids were investigated. The results indicated that higher HDO performance might be due to the bifunctional roles of Ru/C+H3PO4 catalytic system. Lastly, a dual-bed aqueous catalytic system with Ru/C as catalyst was proposed for the liquid alkane production from glucose solution and acid biomass hydrolysate (cassava and corncob). The low temperature (413 K) hydrogenation process was carried out in the first fixed-bed for biomass-derived carbohydrates into polyols, and the high temperature (523 K) hydrodeoxygenation process was carried out in the down-stream bed for polyols into alkanes.In chapter 6, the mechanism of polyol into C5/C6 alkane over bimetallic RuMo catalysts was carefully studied. It not only showed effective catalytic activity but also presented good thermal stability, which was very promising for HDO reaction of polyol. A series of pre- and post-characterization studies (N2-adsorption, XRD, XPS, HRTEM, NH3-TPD, H2-TPR, FTIR spectrums, etc.) were performed over relevant catalysts to study the change of catalytic active sites (physical structure, surface chemistry and acidity distribution). The results indicated that P helped disperse the Ru and Mo on the support and inhibited coke deposition on the catalyst surface during the reaction. The catalyst presented both B and L acid sites. Subsequently, different pretreatments were investigated, which indicated that RuMo/C (pretreated by deionized water) and RuMo/C-P (pretreated by phosphoric acid) presented high HDO performance. Then, different reaction conditions were taken into consideration. Lastly, the results of different carbon supports (AC and CNT) indicated that RuMo/CNT-P presented higher C6 products than that of RuMo/C-P. Thus, relevant characterization analyses were carried out to study the differences between two and catalyitc mechanism.Finally, a series of future investigation and suggestion were also proposed in chapter 7 to further improvement in mechanism study in aqueous catalysis of biomass polyol.