First-order Reaction Equation Research Articles

Analysis of Cleaning Power Using New Cleaning Kinetics and Interfacial Science Studies on Aquatic Toxicity of Surfactants.

Studies devised through the fusion of cleaning and environmental sciences can be summarized as follows: new cleaning kinetics applying a probability density function and a surface chemical approach to the aquatic toxicity of surfactants. Cleaning power analysis using the probability density functional method combines conventional cleaning kinetics using a first-order reaction equation with a risk analysis method using a probability density function. It is possible to analyze the cleaning mechanism from the obtained parameter values. It is also possible to determine whether the interaction between two different cleaning elements corresponds to a synergistic, additive, or offsetting effect. Studies on the aquatic toxicity of surfactants have focused on the surface tension at which surfactants exhibit toxicity, changes in toxicity due to water quality, and biodegradation, and the presence of adsorbed substances have been identified.

Dissipation, Residue Behavior and Dietary Risk Assessment of Difenoconazole on Jujube (Ziziphus jujuba Mill.)

Difenoconazole is a triazole germicide that is usually applied to prevent fungal diseases on crops with high efficiency and safety. Jujube is a spiny Rhamnaceous plant that originated in China more than 4000 years ago and is extensively cultivated in northern China nowadays. To evaluate the safety of difenoconazole in jujube, supervised field trials were carried out in six provinces of China, and the final residue and dissipation behavior of difenoconazole on jujube were determined by gas chromatography (GC). The results showed that when addition levels were 0.02, 0.2, and 2 mg·kg−1, average recoveries of the aforementioned method for difenoconazole in jujube can be put into the range of 73–108%, and relative standard deviation (RSD) was 3–9%. The limit of quantitation (LOQ) for this method was 0.02 mg·kg−1. In the final residue test, difenoconazole was sprayed to deal with the jujube at 100 and 150 mg·kg−1 doses twice or three times, respectively, while the dissipation test was applied only once at a 150 mg·kg−1 dose. Final residue testing results have revealed that when jujube samples were harvested and tested at 7, 14, and 21 days post-application, difenoconazole residues in samples were 0.11–1.59, 0.05–0.77, 0.04–0.63 mg·kg−1, respectively. The dissipation testing results showed that the digestion process of difenoconazole in jujube tends to be a gradual reduction process and the dynamic regularity of the residue dissipation proves consistent with the first-order dynamics reaction equation. The half-life (t1/2) for difenoconazole residue dissipation in Qingdao and Yuncheng was 13.1 days and 16.5 days, respectively. The risk quotient (RQ) was 84.9% lower than 100%, showing that dietary intake risk to difenoconazole was acceptable and the maximum residue limit (MRL) of difenoconazole on jujube is recommended to be 2 mg·kg−1.

Dissolution and Growth Kinetics and the Rate-Controlling Step in Transformation of Amorphous to Crystalline Phase Using Antisolvent Crystallization

The kinetics of the formation of amorphous disodium guanosine 5′-monophosphate and its transformation to the heptahydrate phase were studied under various operating conditions using in situ Raman and focused beam reflectance measurement (FBRM). Supersaturation, solvent composition, feed concentration, addition rate, and viscosity were shown to affect the rate-determining steps of the transformation. The rate-controlling mechanisms in the overall kinetics have been confirmed. The observation of the slurry viscosity of the suspension of the amorphous phase shows the option to observe the phase transformation. The transformation process was affected by the dissolution, growth, and supersaturation in which the rate-controlling step was divided into two sections, such as the initial and later sections of the transformation. The overall rate constants were determined by combining the constants of the dissolution rate and the growth rates of each section. In situ Raman spectroscopy examination of the concentration of solution and solids can determine the rate-limiting processes during the transformation. The zero-order, first-order, and surface reaction equations as kinetic equations are highlighted and compared for the dissolution of the amorphous solids and the growth of the heptahydrate crystals. The dissolution of the amorphous (metastable form) and the growth of the heptahydrate (stable form) were found to be best fitted to the zero-order kinetic model. In particular, the variation of particle size distribution over time can give the rate-determining steps. These results suggest that the data measured by Raman spectroscopy and FBRM can be successfully coupled into a dissolution and growth model to further grasp and interpret the phase transformation. A dissolution rate-controlling step was dominated by a pattern in which both supersaturation and amorphous dissolution decreased simultaneously, and the growth rate-controlling step was shown in a pattern in which either supersaturation or amorphous dissolution was constant. Furthermore, the growth of heptahydrate crystals at a viscosity of the suspension with the amorphous solids below 70 cp and the dissolution of the amorphous solids above it can be used as the key determinant. Using the method developed and the kinetic constants obtained in this work, it is possible to create an appropriate control strategy to produce the desired form in the final product.

Enhancing two-phase anaerobic digestion of mixture of primary and secondary sludge by adding granular activated carbon (GAC): Evaluating acidogenic and methanogenic efficiency

Although the granular activated carbon (GAC) has been proved to enhance conventional single-phase anaerobic digestion (AD), how it impacts on acidogenic and methanogenic fermentation is still unknown. In this study, GAC was introduced to elevate the efficiency of two-phase AD, with mixture of primary and secondary sludge as substrate. Five dosages: 0, 0.1, 0.3, 0.5 and 0.7 g GAC/g TSS (Total Suspended Solids) were investigated to determine influences of GAC. The variations of biogas (hydrogen and methane), volatile fatty acids (VFAs), organics degradation and transformation in extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed. Modified Gompertz model and first-order reaction equation was applied to analyze the kinetics of biogas yield and VFAs utilization, respectively. Sludge reduction, electrical conductance and pH were also quantified to evaluate the system performance. The results showed that GAC could improve two-phase AD performance by enhancing methane production and organics conversion.

Nickel recovery from precipitate of NCA lithium-ion battery leach liquor by using disodium ethylene diamine tetraacetate

The nickel cobalt aluminium oxides (NCA) type Li-ion battery is a type of battery currently used in electric vehicles. The UGM battery team has recycled this type of battery to obtain high purity lithium metal. Aside from lithium, the NCA battery contains high-value metals, nickel is one of them. This experiment aims to test the ease of nickel to chelate with disodium ethylene diamine tetraacetate (EDTA). The experiment was carried out by means of a triple neck flask for 4 hours. The samples were taken at certain minutes and then fitted using a pseudo homogeneous first-order reaction equation. The chelate formed was further processed through multilevel precipitation or electrodialysis to separate nickel. Based on the experiment, nickel formed chelates optimally at 60°C using 0.086 M EDTA with the reaction constant for nickel being 1.4819 min−1. The Arrhenius constant and activation energy for nickel were 3.48×1011min−1 and 76,907 J/mole, respectively.

Effect of Aerating Duration on Hydrocarbon Biodegradation in a Simulated Crude-Oil Polluted Aquatic Environment Undergoing Bioremediation

The aim of this research work was to determine the aerating duration that would be effective in enhancing hydrocarbon biodegradation rate during bioremediation of crude-oil polluted river. Sediment and river-water were placed in four glass troughs labeled CT (control), A, B, and C. The setups were polluted with crude-oil, and allowed undisturbed for 2 weeks. Subsequently, accessible crude-oil on the surface was removed; bacteria and nutrients were then added. Air was bubbled for 3 hours into setups A, B, and C, at daily, 3 days, and 7 days interval respectively. Aeration was not applied to setup CT. On day 1, 7, 14, and 21, hydrocarbon concentration was determined; populations of total heterotrophic bacteria (THB) and hydrocarbon-utilizing bacteria (HUB) were also determined. The time it will take for hydrocarbons in the setups to biodegraded “completely” was calculated using first-order reaction equation. The results obtained showed that 71.43, 86.39, 83.17, and 15.42 % hydrocarbon degradation were obtained in setup A, B, C, and CT respectively. The time it will take for hydrocarbons in the setups to biodegrade “completely” were 129, 89, 101, and 1079 days for A, B, C, and CT respectively. There was slight reduction in population of HUB in setup CT, fairly stable population in setup A, and increase in population of HUB in setups B and C. It is concluded that aerating crude-oil polluted aquatic environment for 3 hours at 3 days interval will be more effective in enhancing hydrocarbon biodegradation rate during bioremediation.

New reactive ionic liquids as carriers in polymer inclusion membranes for transport and separation of Cd(II), Cu(II), Pb(II), and Zn(II) ions from chloride aqueous solutions

Three new reactive ionic liquids (RILs) based on the imidazole derivatives were synthesized and used as carriers in polymer inclusion membranes (PIMs) composed of cellulose triacetate (CTA) as a polymer matrix and o–nitrophenyl octyl ether (NPOE) as a plasticizer. The effect of alkyl chain length (C1, C4, and C8) in the imidazolium cation of RILs on the transport and separation properties was evaluated. From among three synthesized RILs only the RIL with the longest alkyl chain (RILC8_Br) can be successfully applied as the carrier for Cd(II) removal from multicomponent aqueous chloride solution containing also Cu(II), Pb(II), and Zn(II) ions. The effects of the stripping phase composition, HCl concentration in the feed solution, and the carrier content in the membrane on the separation performance and transport effectiveness were studied. The results indicate that the RILC8_Br ionic liquid enables selective transport of Cd(II) ions and their active concentration in the stripping solution with the fluxes reaching a value of 2.7 × 10−10 mol/cm2s. In the investigated feed solution concentration range, the selectivity order was found to be Cd(II) > Zn(II) > Pb(II) ≫ Cu(II) and it was independent of the experimental conditions. For a description of the transport kinetics a model similar to the first-order reversible reaction equations was applied and its applicability was proved.

Effect of Bi5O7I/calcined ZnAlBi-LDHs composites on Cr(VI) removal via adsorption and photocatalytic reduction

Bi5O7I/calcined Bi-doped ZnAl layered double hydroxides (Bi5O7I/ZnAlBi-CLDHs) composites were prepared using the ultrasonic-assisted wet-chemical method, and the removal efficiency of Cr(VI) in an aqueous solution—through the adsorption and photocatalytic reduction of Bi5O7I/ZnAlBi-CLDHs—was investigated. The Bi doping concentration and composition ratio of Bi5O7I/ZnAlBi-CLDHs influence the removal rate of Cr(VI), and the optimal removal ability of Bi5O7I/ZnAlBi-LDHs is attained with 3% Bi doping and a Bi5O7I/ZnAlBi-CLDHs ratio of 1/10. The adsorption rate of Cr(VI) reaches 84% when infiltrating Bi5O7I/ZnAlBi-CLDHs for 60 min, while a higher removal rate of 98%, is attained through photocatalysis with visible light irradiation. The experimental data fit well with the pseudo second-order kinetic model, Langmuir adsorption isotherm model and the first-order reaction equation, which explains the possible Cr(VI) removal mechanism based on the fitting data. XPS results prove that about 61% of the Cr(VI) is gradually reduced to safe Cr(III) through the photocatalysis of Bi5O7I/ZnAlBi-CLDHs by the light irradiation duration 6 h. These results indicated that harmful Cr(VI) can be effectively removed by as-prepared Bi5O7I/ZnAlBi-CLDHs for water security, and that Bi5O7I/ZnAlBi-CLDHs provide a new prospect for the removal of Cr(VI) through adsorption and photocatalysis.

Combustion Characteristics and Kinetic Analysis of Biomass Pellet Fuel Using Thermogravimetric Analysis

Biomass pellet fuel is one of the development directions of renewable energy. The purpose of the article is to study the combustion characteristics of five kinds of biomass pellet fuel that can be used as biomass fuel and analyze their combustion kinetics. The thermogravimetric method (TG method) was used to analyze the combustion characteristics of five kinds of biomass pellet fuel and to calculate the index S of comprehensive combustion characteristic. The Arrhenius equation and the Coats–Redfern method were used to analyze the combustion kinetics of five kinds of biomass pellet fuel. The activation energy and pre-exponential factor were obtained according to different temperature ranges. Conclusions are as follows: The pyrolysis of five kinds of biomass pellet fuel mainly includes three stages: (1) water evaporation stage, (2) volatile component combustion stage, (3) fixed carbon oxidation stage. The TG curves of five kinds of biomass pellet fuel are roughly the same at the same heating rate. The peaks of thermal weight loss rate and maximum degradation rate are both in the high temperature range. The differential thermal gravity (DTG) curves of five kinds of biomass pellet fuel have an obvious peak. The peak temperature of the largest peak in the DTG curves is 280–310 °C. The first-order reaction equation is used to obtain the kinetic parameters in stages. The correlation coefficients are bigger than the value of 0.92. The fitting results are in good agreement with the experimental results. The activation energy of each sample is basically the same in each stage. The value in the volatile matter combustion stage is 56–542 kJ/mol, and the activation energy of the carbon layer slowly increases rapidly. The five kinds of biomass pellet fuels have good combustion characteristics and kinetic characteristics, and they can be promoted and applied as biomass pellet fuels in the future.

Gel formation and its relaxation mechanism of shear-induced aqueous suspensions comprised of bentonite and heptaethylene oleyl ether

We considered the gelation and its relaxation mechanism of a shear-induced bentonite / heptaethylene oleyl ether (abbreviated as C18:1E7) aqueous suspension based on the analysis of Rheo-SALS. When bentonite / C18:1E7 aqueous suspension formed the shake-gel, the concentration of bentonite was greater than or equal to the critical concentration of c* = 1.3 wt% where hydrodynamic interactions occur. The relationship between the time ts when the shear thickening occurs and the bentonite / surfactant concentration (c - cs) can be described by the first-order reaction equation, and ts can be further reduced with the applied shearing.The gel formation time and the relaxation time were affected by the shear hysteresis. We found that the formation and the relaxation (breakdown) of gels comprising bentonite particles did not follow the same pathway. Thus, Shear induced gel formation is due to the percolation transition by the infinite network structure in which the anisotropic orientation of bentonite particles grows. In contrast, the relaxation (breakdown) of the gel proceeds by the isotropic diffusion of individual bentonite particles forming the network structure.

Study on Hydrolysis Reaction Rate of Several Chemical Warfare Agents

According to the first-order kinetic reaction equation, the hydrolysis rate constants of homogeneous and heterogeneous phase of eight poisons under different conditions were calculated, and the relationship between hydrolysis rate constants and temperature was obtained according to the arrhenius formula, and the activation energy of hydrolysis reaction of some poisons was calculated. The evolution curve of homogeneous hydrolysis rate of 0.5 g/L HD with time was collected by T-135 method, and the hydrolysis rate was 0.1 min-1 and the half-life was 7 min. Poison concentration, pH of system, environmental temperature and structural composition of soil all affect the hydrolysis rate of Chemical Warfare Agents.

Some Critical Remarks about Mathematical Model Used for the Description of Transport Kinetics in Polymer Inclusion Membrane Systems.

Two kinetic models which are applied for the description of metal ion transport in polymer inclusion membrane (PIM) systems are presented and compared. The models were fitted to the real experimental data of Zn(II), Cd(II), Cu(II), and Pb(II) simultaneous transport through PIM with di-(2-ethylhexyl)phosphoric acid (D2EHPA) as a carrier, o-nitrophenyl octyl ether (NPOE) as a plasticizer, and cellulose triacetate (CTA) as a polymer matrix. The selected membrane was composed of 43 wt. % D2EHPA, 19 wt. % NPOE, and 38 wt. % CTA. The results indicated that the calculated initial fluxes (from 2 × 10−11 up to 9 × 10−10 mol/cm2s) are similar to the values observed by other authors in systems operating under similar conditions. It was found that one of the most frequently applied models based on an equation similar to the first-order chemical reaction equation leads to abnormal distribution of residuals. It was also found that application of this model causes some problems with curve fitting and leads to the underestimation of permeability coefficients and initial maximum fluxes. Therefore, a new model has been proposed to describe the transport kinetics in PIM systems. This new model, based on an equation similar to the first-order chemical reaction equation with equilibrium, was successfully applied. The fit of this model to the experimental data is much better and makes it possible to determine more precisely the initial maximum flux as the parameter describing the transport efficiency.

Anaerobic biodegradation of acetochlor by acclimated sludge and its anaerobic catabolic pathway

Acetochlor is a chloroacetamide herbicide that has been widely used for weed control in recent decades. The contamination from its residue in the environment has raised major serious concerns. The aerobic degradation of acetochlor has been well studied; however, little is known regarding its anaerobic degradation. In the study, anaerobic sludge with high acetochlor degradation efficiency was obtained by pressure acclimation in a continuous flow anaerobic reactor. The acetochlor degradation dynamics followed a first-order kinetic reaction equation. The acclimated sludge could degrade six chloroacetamide herbicides with the degradation efficiencies observed as alachlor > acetochlor > propisochlor > butachlor > pretilachlor > metolachlor, and the N-alkoxyalkyl structure of these herbicides significantly affected their biodegradability. Five metabolites, 2-ethyl-6-methyl-N-(ethoxymethyl)-acetanilide, N-(2-methyl-6-ethylphenyl) acetamide, N-2-ethylphenyl acetamide, N-2-ethylphenyl formamide and 2-ethyl-N-carboxyl aniline were identified, and a putative anaerobic acetochlor degradation pathway, initiated by dechlorination, was subsequently proposed. During acclimation, the community diversity of both eubacteria and archaea in the anaerobic sludge decreased, while the abundance of microbes belonging to genera Sporomusa, Sporobacterium, Dechloromonas, Azotobacter and Methanobacterium were significantly increased and dominated the acclimated sludge, and showing a positive correlation with the acetochlor degradation capacity. These findings should be valuable to elucidate the mechanisms associated with the anaerobic catabolism of acetochlor and facilitate the engineering application of anaerobic treatment for removing acetochlor from wastewater.

Preparation and Photochromic Performance of Homogeneous Phase Nitrocellulose Membrane Grafting Spirooxazine Moieties

The synthesis of 1,3,3-trimethyl-9′-acryloxyspiro[indoline-2,3′(3H)naphtho[2,1-b][l,4]-oxazine] (AISO) was carried out by catalytic esterification of 1,3,3-trimethyl-9′-hydroxyspiro-[indoline-2,3′(3H)naphtho[2,1-b][l,4]oxazine] (SO–OH) and acrylic acid in the presence of 1,3-dicyclohexylcarbodiimide (DCC) and N-dimethylaminopyridine (DMAP). Then, the synthesis of the target copolymer (NC-g-AISO) was was carried out by benzoyl peroxide (BPO)-induced graft copolymerization of the AISO monomer onto nitrocellulose (NC) in a homogeneous methyl isobutyl ketone medium. The structure of NC-g-AISO was characterized by Fourier transform infrared (IR) spectroscopy, 13C Nuclear Magnetic Resonance (NMR) spectra and thermogravimetric (TG) analysis. The photochromic properties of NC-g-AISO were investigated by examining UV–Vis spectra in ethyl acetate solution and solid membrane. Compared with the AISO monomer in ethyl acetate solution, the thermal color decay stability of the colored form of NC-g-AISO in ethyl acetate solution and in solid membrane improved significantly. The thermal color decay reaction rate constants in ethyl acetate solution and membrane at 25 °C were 1.77 × 10–2 and 1.36 × 10–3 s–1, respectively, fitted using the first-order reaction equation. After ten photochromic cycles, the relative absorption intensity of the colored form of NC-g-AISO decreased by 0.85%, indicating that the NC-g-AISO membrane has good reversible photochromic behavior.

The improved treatment of liquid crystals into non-hazardous molecules using a microwave-assisted hydrothermal method

Liquid crystal (LC), as a crucial component of liquid crystal display (LCD), improperly treatment of which will possibly impair ecosystems and human health. In view of the advantages of hydrothermal reaction and microwave irradiation, this paper intensively studied the process of microwave-assisted hydrothermal (MWAH) decomposition of LC wastes. The experimental materials include a kind of refractory fluorinated liquid crystal commonly used in thin-film transistor LCD, and its mixture with the other two typical liquid crystal monomers in the waste low-end display panels. Under the MWAH process, the optimized condition for thorough decomposition of 0.67 g.L−1 fluorinated liquid crystal is 0.653 mol.L−1 H2O2, 1 g.L−1 AC, 300 mL water, 250 °C and 7 min. The superiority of microwave in enhancing hydrothermal treatment efficiency was verified by the first-order kinetic reaction equation fitted for the decomposition process under optimal condition, along with two possible decomposition pathways tentatively proposed after characterizing the intermediate products. Under the same condition, 1 g.L−1 mixture of fluorinated liquid crystal and the other two liquid crystal monomers were entirely decomposed with no harmful byproduct detected, suggesting that microwave irradiation could effectively promote the hydrothermal decomposition of liquid crystal wastes.

Preparation and analysis of photochromic behavior of carboxymethyl chitin derivatives containing spiropyran moieties

ABSTRACT 1ʹ-(2-Acryloxyethyl)-3,3ʹ-dimethyl-6-nitrospiro[2 H-1-benzopyran-2,2ʹ-indoline] (SPA) was synthesized and grafted onto a water-soluble carboxymethyl chitin (CMCH) macromolecule to prepare a photochromic copolymer (CMCH-g-SPA). The structure of CMCH-g-SPA was characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, X-ray diffraction (XRD) analysis, water-solubility evaluation, and UV-vis spectroscopy. XRD patterns of CMCH-g-SPA revealed that grafting copolymerization disrupts the CMCH semicrystalline structure, thus improving water solubility. UV-vis spectroscopy results supported the negative photochromic behavior of the merocyanine (MC) form of CMCH-g-SPA (CMCH-g-MCA) present in a water solution of the target copolymer. In addition to high solvent polarity, the intermolecular and intramolecular electrostatic attraction between the indolenine cation and the COO− anion were found to be influencing factors, which stabilize these MC form of spiropyran groups grafted onto CMCH. In a water solution, visible light bleaching was completed over a short period (8 minutes) under artificial visible light irradiation and the thermal coloration reaction, whose rate constant at 25 °C was 4.64 × 10−4 s−1, which fit the first-order reaction equation. After ten photochromic cycles in water solution, the relative absorption intensity of CMCH-g-MCA decreased by 7.92%.

Adsorption and photocatalytic reduction of aqueous Cr(VI) by Fe3O4-ZnAl-layered double hydroxide/TiO2 composites

To evaluate the synergetic adsorption capacity of layered double hydroxide (LDH) and photocatalytic reduction property of TiO2 for aqueous Cr(VI), the Fe3O4-ZnAl-LDH and TiO2 composites (FLT) were prepared via sol-gel method. The removal efficiency of FLT composites for Cr(VI) changed with the mass ratio of Fe3O4-LDH/TiO2, and the optimal ratio was 20% (FLT-2). The adsorption efficiencies of 100 mg FLT-2 were 74% and 64% for 20 and 50 mg/L Cr(VI) solution, and the total removal ratios of Cr(VI) were all over 97% after UV irradiation. The experimental data of adsorption kinetic, adsorption isothermal, and photocatalytic reduction were consistent with the pseudo-second-order, Langmuir, and first-order reaction equations, respectively. From the X–ray photoelectron spectra analysis, FLT composites adsorbed Cr(VI) directly via surface complexation, also reduced aqueous Cr(VI) to Cr(III). The photocurrent and electrochemical impedance spectroscopy of FLT composites indicated the photo-induced electron-hole pairs were separated effectively. The regeneration results show that the FLT composites had good stability and reusability after five consecutive cycles. Therefore, FLT composites are promising materials in the disposal of wastewater containing Cr(VI).

High-efficient biodegradation of refractory dye by a new bacterial flora DDMY1 under different conditions

Industrial wastewater with refractory dyes is still considered as one kind of serious pollution. Biological treatments have shown great potential for the biodegradation of dyes. A new natural bacterial flora DDMY1 with efficient decolorization performance of azo dye reactive black 5 (RB5) was obtained from activated sludge by concentration gradient domestication. Morphological analysis, growth test, decolorization assay of different parameters, kinetics study and high-throughput sequencing were performed in this study. Morphological analysis showed the features of flora DDMY1 and growth curves emerged the temperature range suitable for the growth of flora DDMY1. Results of decolorization assays indicated that xylose and yeast extract could enhance the decolorization effect and flora DDMY1 could decolorize RB5 not only in wide ranges of pH values (4.0–9.0) and initial dye concentration (100–1000 mg L−1), but also in the optimum temperature (40 °C) and NaCl concentration (1.5%, w/v). Kinetics study of RB5 decolorization at 30–40 °C conformed to the first-order kinetic reaction equation. High-throughput sequencing analysis revealed the community structure of flora DDMY1 and the dominant genus unclassified_o_Pseudomonadales, which had synergistic effect on decolorization with unclassified_f_Alcaligenaceae, Pseudomonas and other genera. Findings of this study revealed a sort of natural bacterial flora that could accommodate different wastewater conditions and remove high-concentration refractory dyes efficiently. These results also indicated the possibility of treating dyeing wastewater on a large scale with different conditions.

The characteristics of decomposition and nutrient release of Vicia villosa under different fertilization treatments.

The effects of three fertilization treatments (no fertilizer, nitrogen fertilizer, and lime) on the characteristics of Vicia villosa decomposition and nutrient release were studied using the nylon bag method in the fields. The results showed that the cumulative decomposition rate of V. villosa was 65.3%-72.5% across the three fertilization treatments. V. villosa decomposed rapidly during 0-11 d, then slowed down and tended to be stable. The nutrient release rates across the three treatments were potassium > phosphorus > carbon > nitrogen. At the end of the experiment (148 d), the cumulative release rates of carbon, nitrogen, phosphorus and potassium were 83.6%-84.6%, 78.2%-81.2%, 89.8%-91.4% and 96.3%-97.0%, respectively. During the whole decomposition period, the characteristics of nitrogen release and decomposition of V. villosa were similar. Compared with no fertilizer treatment, lime application promoted decomposition and release of nitrogen, phosphorus and potassium. Nitrogen fertilizer application promoted phosphorus release but inhibited potassium release. Both nitrogen application and lime application had no significant effect on carbon release. The application of nitrogen fertilizer promoted the decomposition of V. villosa and nitrogen release in 0-11 d, but inhibited those processes in 11-148 d. The first-order kinetic reaction equation and logarithmic function equation well fitted the characteristics of V. villosa decomposition and the release of carbon, nitrogen, phosphorus and potassium in the rice fields of South Henan. The characteristic parameters of the equation were significantly correlated with the decomposition rate and nutrient release rate of V. villosa. In summary, lime application was better than nitrogen fertili-zer in promoting decomposition and nutrient release of V. villosa. Moreover, the parameters of the first-order kinetic equation and logarithmic function equation showed a good description of decomposition and nutrient release of V. villosa.

Impact of Water Pressure on the Organic Matter Evolution from Hydrous Pyrolysis

Deep oil and gas, as an important part to make up the energy-deficient. A series of breakthroughs had been made in their exploration and development in the past few years. However, the effects of deep fluids during hydrocarbon formation and evolution are still an ambiguous problem. Therefore, to investigate the effect of water pressure (PW) on hydrocarbon generation and thermal evolution of type-I, type-II, and type-III kerogens in a deeper stratum, three series of pyrolysis experiments were conducted on three samples with different kerogen types (types II₁, I, and III in TC, YMS, and XJ samples, respectively) in a high-temperature, high-pressure simulator. The type-I kerogen was pyrolyzed with 5, 20, 35, 50, 65, and 80 MPa water pressure at 375 °C for 48 h, whereas the type-II and type-III kerogens were pyrolyzed with 10, 20, 30, 40, 50, and 60 MPa water pressure at 350 °C for 48 h. The results showed that there was a threshold pressure PW affecting liquid hydrocarbons. In addition, before the threshold pressure, PW played a role in promoting, but then it was the inhibiting. For gaseous hydrocarbons, while the pressure effects and results were the same as with liquid hydrocarbons in TC samples under the near-critical or critical state, they had no obvious effects in YMS and XJ samples before the critical state, which proved that the organic matter (OM) evolution was associated with the state of fluid in the reaction system and the effects were stronger when the fluid was under the near-critical or critical state than when it is not under this state. The reasons could be concluded as follows: (1) the different properties of water, as the ionization product constant of water (K(w)) was higher in TC samples and may provide more H⁺ to participate in the OM reactions compared to YMS and XJ samples. Moreover, the particular characteristics of intersolubility with organic solvent occurred under near-critical or critical states, resulting in the more water-soluble hydrocarbons being expelled in TC samples. (2) Chemical mechanism: based on the first-order reaction equation for oil–gas generation and essential characters of samples and experiments, it can be concluded that the influence degree of PW on OM evolution was related to the type of OM, the thermal maturity as well as the nature of water. (3) Physical mechanism: the vapor in free space and generated hydrocarbons in pores were in a dynamic balance state, which also resulted in the existence of threshold pressure PW affecting OM evolution. Therefore, understanding the effects of PW on OM evolution would help us to study the oil–gas generation accurately in actual geology and help preferably in oil–gas exploration and exploitation.