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Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This is an article in the field of mining engineering. The diatomite was modified with sodium dodecyl sulfonate and ferroferric oxide, and the influence of external factors on the adsorption effect was analyzed. And the experiment of the phase composition change and the microstructure change after the modified diatomite adsorbs heavy metal ions was carried out. The results show that when the modified diatomite content is 4 g/L, the adsorption time is 40 min, the temperature is set to 30 ℃, the pH value is set to 5, and the initial concentration is set to 200 mg/L, the adsorption of the modified diatomite is relatively good. The fitting degree of the Freundlich model to the test curve is above 0.90, and the fitting degree of the Langmuir model to the test curve is below 0.9, which shows that the Freundlich isotherm adsorption model is more suitable for the change law of the adsorption of heavy metal lead ions on modified diatomite. There is no significant difference in the characteristic diffraction peaks of the XRD pattern before and after the adsorption of lead ions on the modified diatomite. Only the peak intensity of the diffraction peak is reduced. However, the other mineral components inside the modified diatomite remain unchanged and the structure does not change significantly. This also shows that modified diatomaceous earth can effectively adsorb lead ions in sewage. However, the adsorption process is basically physical adsorption.

This is an article in the field of environmental engineering. In order to study the effect of kaolin on the adsorption performance of wastewater containing Cu2+ and Pb2+, experiments on the adsorption of heavy metal ions by kaolin under different initial concentrations, temperatures, adsorption time, kaolin content and pH values are carried out. And analyzed the results of Cu2+ and Pb2+ co-adsorption test by kaolin. The results show that the adsorption effect of kaolin on metal Pb2+ ions is better than the adsorption effect of kaolin on metal Cu2+ ions. Combining the test results and economic benefits, when the initial concentration is 200 mg/L, the pH is 6, the temperature is 30 °C, the kaolin content is 1.5 g, and the adsorption time is 2.0 h, Kaolin has the best adsorption effect on metal Pb2+ and Cu2+ ions. The adsorption capacity of metal Pb2+ ions reached 56.38, 56.22, 58.76, 35.75, and 42.42 mg/g, respectively. The adsorption capacity of metallic Cu2+ ions is 45.99, 47.45, 47.27, 25.26, 22.52 mg/g. On the whole, the adsorption capacity of kaolin for co-adsorbed metal ions (Cu2+, Pb2+) is smaller than that of a single ion. This is because two metal ions will affect each other's adsorption process during the adsorption process. The fit of Langmuir model to the test curve is much higher than the fit of Freundlich model to the test curve. This shows that the Langmuir isotherm adsorption model is more suitable for the change law of the amount of metal ions adsorbed by kaolin. Furthermore, it is proved that the adsorption of heavy metal ions by kaolin belongs to surface adsorption, and the adsorbed heavy metal ions exist independently of each other.

The effect of adsorption time on the performance of pressure swing adsorption (PSA) oxy- gen production process was experimentally investigated and a concentration wave model was proposed for analyzing the mass transfer characteristics and calculating the optimal adsorption time during the PSA process. The results showed that the shape of N₂ loading profile at adsorption step changed with time and axial position, and the propagation velocity of the N₂ concentration wave with ideal conditions was greater than the practical propagation velocity. The limited heat and mass transfer resistance slowed down the propagation of the concentration wave during the practical adsorption process, and the reduction degree of the concentration wave velocity was about 26%. The errors between the opti- mal adsorption time calculated though the concentration wave model and the experimental adsorption time were within 0. 5 s. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since the influence of carbon dioxide (CO2) on the dynamic interfacial tension of crude oil and aqueous solutions at the elevated temperatures and pressures is an important issue, this investigation is aimed to measure the IFT of crude oil/water, CO2, and carbonated water. The measured values reveal that the IFTs of crude oil/CO2 are decreased through the first interval, while a gradual and continuous reduction in IFT is obtained at the second interval. Although both intercepts and slopes of the first interval lines are more than the second interval for all the studied temperatures, they show a similar trend as a function of temperature. The used vanishing IFT method measurement reveals that the minimum miscibility pressure (MMP), first contact miscibility pressure, and intersection point (where the slopes of the linear curves change) of two linear equations have a linear increasing trend as temperature changes. However, this trend was not observed for the aqueous solution saturated with CO2 (i.e., carbonated water) which can be related to the difference between liquid- and gas-phase behavior as well as the formation of carbonic acid in the carbonated water process. IFT values reduced from 18.6 mN/m (@ pH = 8) to 0.3 mN/m (@ pH = 14) with an increase in pH of the aqueous solution, while miscibility conditions can be obtained for CO2 cases at pressures higher than the MMP points. Considerably higher IFT values were measured in the presence of water and carbonated water in the range of 9.1–17.5 mN/m and 12.2–17.4 mN/m, respectively. The most important feature of the CW process can be the swelling factor of crude oil due to the fact that the oil swelling of up to 40% was achieved at elevated temperature (75 °C) and pressure (4500 psi) after only1600 s. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) were developed by exploiting the photovoltaic effect to convert solar energy into electrical energy. The photoanode layer thickness significantly affects the semiconductor film's ability to carry electronic charges, adsorb sensitizing dye molecules, and lower the recombination of photo-excited electrons injected into the semiconductor. This study investigated the dependence of the zinc oxide (ZnO) photoanode thin-film thickness and the film soaking time in N719 dye on the photocurrent–voltage characteristics. The ZnO photoanode was applied to glass using the doctor blade method. The thickness was varied by changing the scotch tape layers. The ZnO-based DSSC attained an efficiency of 2.77% with three-layered photoanodes soaked in the dye for three hours, compared to a maximum efficiency of 0.68% that was achieved with three cycles using the dip-coating method in other research. The layer thickness of the ZnO photoanode and its optimal adsorption time for the dye are important parameters that determine the efficiency of the DSSC. Therefore, this work provides important insights to further improve the performance of DSSCs. [ABSTRACT FROM AUTHOR]

The blast furnace slag was modified with DTAC to prepare a low-cost and environment-friendly adsorbent for the treatment of dye wastewater. The study analyzes theadsorbent dose, adsorption time, initial dye concentration and pH value on the adsorption capacity of KN-R reactive brilliant blue from the modified slag , and the variation rule of characterization of the modified slag was also analyzed. The results show that when the amount of modified slag is 10 g/L, the initial concentration of dye is 60 mg/L, the pH value is 2, and the adsorption time is 120 min, the maximum decolorization rate of the modified slag can reach 96%, and the initial concentration of 150 mg/L is the optimal solubility, the decolorization rate and adsorption capacity are both high at this concentration. Through XRD and FTIR tests, the characterization characteristics of slag and modified slag were compared and analyzed. It was found that DTAC could better modify slag, and the adsorption capacity of modified slag was significantly improved.

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since knowing the effect of salt type is a vital parameter during smart-water injection for enhanced oil recovery (EOR) purposes, surface-free energies on the carbonate surface contacted by crude oil and different aqueous solutions with 0.7 ionic strength (about the ionic strength of seawater) are studied for solutions containing NaCl, Na2SO4, KCl, CaCl2, MgCl2, and MgSO4. For this purpose, the interfacial tension (IFT) of crude oil/aqueous solution and contact angle of oil/rock/brine are measured concomitant with the calculation of works of cohesion (WC) and adhesion (WA) as well as spreading coefficient (SC). Maximum equilibrium IFT reduction was observed for MgSO4 (from 22.7 to 12.71 mN.m−1). Besides, the calculated adsorption times using the exponential decay model reveal that the chloride salts of MgCl2 and KCl has the minimum and maximum adsorption time of 1600 s and 3400 s, respectively. Moreover, the contact angle measurements demonstrate that it is possible to change the wettability condition of rock surface from strongly oil-wet to strongly water-wet (about 20°) using Na2SO4 while the other utilized salts can change the contact angle from 170° to neutral wetness condition of 100°. The obtained results show that the best SC was obtained for DW due to its significant wettability alteration capability (from strongly oil-wet toward neutral state) compared with brine solutions. To sum up, according to the results it can be concluded that solution congaing MgSO4 can introduce the lowest IFT value and the highest wettability alteration from the initial strongly oil-wet state toward a neutral state, while Na2SO4 solution leading the lowest contact angle of about 20° which is the most favorable condition (strongly water-wet). [ABSTRACT FROM AUTHOR]

The dynamic adsorption process of a semi-flexible polymer onto homogeneous attractive surfaces is studied using dynamic Monte Carlo simulations. The adsorption time increases linearly with the bending rigidity, but it tends to be less dependent on the bending rigidity at large polymer-surface attraction strength, indicating that the semi-flexible polymer is softened by surface attraction during the adsorption process. The scaling relation between the adsorption time and polymer length is also studied, and different scaling exponents are found for rigid polymer and for flexible one. The adsorption time is influenced significantly by non-adsorbed monomers as they remain their original positions at time less than the adsorption time, that changes the relation between the adsorption time and the polymer-surface attraction strength. The semi-flexible polymer is finally adsorbed on the surface at about four times the adsorption time. Image 10 • Adsorption time is dependent on polymer rigidity and surface attraction strength. • Adsorption time increases in different ways for rigid and flexible polymers. • Adsorption time is influenced significantly by non-adsorbed monomers. • Adsorption of semi-flexible polymer can be divided into two steps. [ABSTRACT FROM AUTHOR]

Abstract Concerns about climate change have persuaded the researchers to examine CO 2 injection in the form of carbonated water (CW) into oil reservoir as a safe and effective CO 2 storage and enhanced oil recovery process. Although interfacial tension (IFT) between crude oil and injected fluid has a vital role on the displacement of fluids in porous media, the effect of CO 2 and crude oil type on the dynamic IFT of crude oil under different operational conditions is not well understood. Accordingly, this study was carried out to assess the effects of temperature, pressure, crude oil type and CO 2 on the dynamic IFT of crude oil/CW. To achieve this goal, two types of crude oil were provided from southern Iranian oil reservoirs and dynamic IFTs with CW were measured in a wide range of temperatures and pressures (i.e. temperature range of 30–80 °C and pressure range of 500–4000 psi); the obtained results were compared with the system without CO 2. In addition, the adsorption time of carbonated aqueous phase/crude oil, obtained based on the mono exponential decay model, was also compared with unadulterated water/crude oil system. The outcome of this study showed that crude oil type has the most significant effect on the IFT of crude oil/CW compared to pressure, temperature and CO 2 content. In more details, the IFT of crude oil/CW can be affected by the amount and type of acidic/basic components in the crude oil as well as pH of the aqueous solution. Besides, the obtained results revealed that the effect of temperature was more considerable on the IFT of the heavy crude oil compared with the light crude oil in both studied aqueous solutions (i.e. unadulterated water and CW). Although the inversion phase temperature was obtained for unadulterated water/studied crude oils at all studied pressures, this phenomenon was not observed for crude oil/CW at elevated pressure, due to the high amount of CO 2 at this condition. Highlights • Dynamic interfacial tension (IFT) of crude oil/carbonated water (CW) was studied. • Effects of temperature, pressure and crude oil type were examined. • Crude oil type showed the most significant effect on the IFT of crude oil/CW. • The effect of temperature on the heavy crude oil was higher than light crude oil. • Competition between CO 2 and ingenious surfactants ionization determined IFT trend. [ABSTRACT FROM AUTHOR]

The photo extraction of rubidium atoms from the bulk of a photonic crystal has been investigated. It has been found that in the case of irradiation of the crystal in the stop band where the desorbing light does not penetrate deeply, the separation of atoms occurs practically from its surface, so that the density of desorbed atoms in the cell decreases only exponentially. In the case of irradiation of the crystal outside the stop band, the bulk of the crystal is irradiated almost completely. In this connection, the exponential decrease in the density of atoms in the cell is replaced by its relatively slow reduction of diffusion nature. The bulk diffusion coefficient of rubidium atoms in the photonic crystal was measured to be 2 · 10−8 cm2/s. [ABSTRACT FROM AUTHOR]

Adsorption deformation significantly affects the seepage characteristics of coal. However, effect of sorption time on coal permeability and gas pressure has not been investigated systematically. In this study, the sorption experiment of coal samples is conducted to elaborate the importance of sorption equilibration time. Then a coupled coal deformation and gas flow model is established considering the sorption characteristic and permeability evolution. This coupled model is implemented through finite element method to analyze the effect of sorption time on coal permeability and gas pressure. The simulation results reveal that the gas pressure of the coal will change with the adsorption time. The fracture pressure maintains a high level while the matrix pressure is relatively low during the adsorption process. The sorption time has a great influence on the distribution of gas pressure. The smaller the adsorption time is, the lower the gas pressure becomes. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An experimental and statistical study was performed for the purification of hydrogen in an H/CO mixture using the PSA process with activated carbon. This process has been extensively used for the high purification of gas mixtures. Central composite design (CCD) was used for the modeling and optimization of the process, regardless of complex and time-consuming equations generally employed in the literature. The statistical analysis of models, as obtained from the CCD method, revealed that distinct second-order polynomial equations, with F-value more than 200, p-value less than 0.0001, and R-squared more than 0.9900, could predict the experimental data for purity, recovery and productivity of hydrogen. Based on the established models, as the purge-to-feed (P/F) ratio increased, the purity increased, while the recovery and productivity decreased. The recovery and productivity first increased and then decreased as adsorption time increased. Thus, the optimal condition of the PSA process was obtained using the CCD models. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The critical adsorption temperature (T CAP) and adsorption process of end-grafted polymer chains with grafting density f on a homogeneous, attractive surface are studied using Langevin dynamics simulations. Results show that T CAP is roughly a constant at low f far below the critical grafting density f c which separates the polymer brush from the mushroom region, then it decreases with increasing f due to the inter-polymer repulsive interactions, and finally becomes a constant roughly independent of polymer length at f > f c because only the chain sections closest to the surface are involved in the adsorption process. However, T CAP is only estimated for f less than f limit = 1.5/ N where more than 50% of polymer monomers (N) per chain can be adsorbed at low temperature. The dynamic adsorption process for the polymer chains below f limit and T CAP shows that the adsorption time τ ads (for polymer chains from desorbed state to adsorbed state) changes non-monotonically with f and exhibits a maximum at f τ,max = 0.5 f limit. The increase of τ ads below f τ,max is due to the inter-polymer repulsive interactions which hinder the adsorption. Whereas the decrease of τ ads at high f is attributed to the decrease of the number of adsorbed monomers per chain. Our study reveals that the critical adsorption temperature and adsorption process of the end-grafted polymer chains are dependent on the grafting density. [Display omitted] • Critical adsorption temperature of polymer is dependent on the grafting density. • Inter-polymer repulsive interactions decrease the critical adsorption temperature. • Critical adsorption temperature decreases fast near the critical grafting density. • Inter-polymer repulsive interactions increase the adsorption time of polymer. • Adsorption time decreases when the number of adsorbed monomers per chain decreases. [ABSTRACT FROM AUTHOR]

Salivary pellicle is a biofilm that is formed by the selective adsorption of salivary proteins. Almost all the functions of the salivary pellicle (lubricating properties, anti-caries properties, etc.) are closely associated with its adhesion strength to tooth surface. The objective of this study was to investigate the effect of adsorption time on the adhesion strength between salivary pellicle and human tooth enamel, aiming to understand what act as the determinant of the interfacial adhesion. In this study, human tooth enamel samples were immersed in human whole saliva in vitro to obtain a salivary pellicle on the surface of enamel. Immersion treatments lasting up to 1, 3, 10 and 60 min were conducted, respectively. Nano-scratch tests were conducted on the surface of enamel after different adsorption times. The wettability of enamel surface was measured through water contact angle. Results showed that the shear energy between salivary pellicle and enamel surface increased exponentially with the adsorption time. The adhesion force between salivary pellicle and bare enamel surface was more than twice that between salivary pellicle and salivary pellicle. It was found that both the wettability and zeta potential of enamel increased obviously after 1 min saliva-adsorption treatment, and then they almost kept stable as the adsorption time further increased. In summary, the adhesion strength between initial salivary pellicle and enamel surface was much higher than that between initial salivary pellicle and outer salivary pellicle. It seemed that electrostatic interaction contributed to the adhesion between the initial salivary pellicle and enamel surface, but not to the adhesion between the initial and outer salivary pellicle. The results would be helpful to extend the understanding of the adhesion mechanism of salivary pellicle and then to develop new artificial saliva and dental restorative materials. [ABSTRACT FROM AUTHOR]

Cadmium sulfide (CdS) quantum dots (QDs) were adsorbed on a titanium dioxide (TiO) nanoporous film by successive ionic layer adsorption and reaction (SILAR) method with different adsorption times to study the influences of different SILAR adsorption times on CdS quantum dot-sensitized solar cells (QDSCs). The optical properties of CdS sensitized TiO films were studied by scanning electron microscopy and UV-Vis absorbance spectroscopy. The particle size of the CdS QDs was approximated using the effective mass approximation theory from the absorbance spectra. The photovoltaic characteristics of the CdS QDSCs were analyzed by I- V characteristics and electrochemical impedance spectroscopy under air mass 1.5 illumination. As a result, the particle size of the CdS QDs became larger and light harvesting was enhanced with increasing SILAR adsorption time. The maximum photovoltaic conversion efficiency of the CdS QDSCs (1.86%) was obtained at the SILAR adsorption time of 30 min with the highest short circuit current density and lowest charge transfer resistance. [ABSTRACT FROM AUTHOR]

Abstract: Lubrication is the primary function of saliva in the mouth, which is closely associated with the adsorbed salivary proteins. Previous studies have suggested that the amount of adsorbed salivary proteins on the surfaces of human teeth depends on adsorption time. The objective of this study is to investigate the effect of adsorption time on the lubricating performance of human whole saliva. In this paper, nano-scratch tests were performed on the salivary pellicle formed on human tooth enamel after different adsorption times. Adsorption was conducted in vitro by immersing the enamel specimens in human saliva under different time intervals. The results showed that at the early stage of adsorption, a thin and dense salivary pellicle was formed on the enamel surface. As the adsorption time increased, some scattered protuberances appeared on the surface of the initial layer. With the adsorption time further increasing, more and more protuberances appeared. Finally the initial layer was completely covered by the protuberances. The amount of proteins in the salivary pellicle increased with the adsorption time, but no significant variation occurred to the kinds of the adsorbed proteins. Friction-wear tests by a nano-scratch tester indicated that both the friction coefficient and wear loss of the enamel surface significantly decreased after the surface was covered with salivary pellicle. For the saliva-adsorbed enamel surface, the friction coefficient increased with the adsorption time, but no obvious changes happened to either the wear morphology or the wear loss. In summary, the salivary pellicle changed with the adsorption time, and the initial salivary pellicle exhibited an excellent lubricating effect on human tooth enamel. The results would be helpful to extend the understanding of the lubricating mechanism of human whole saliva and then to develop new artificial saliva. [Copyright &y& Elsevier]

Abstract: The desorption characteristics of coalbed in China are affected by many factors. The desorption ratio of coalbed gas is approximately 40%, and mostly less than 70%, and it is affected by gas content and coalbed pressure. Most of the desorption time values are between 0.1883 and 19.17d, and the time span of high-rank coal is the highest, which can reach 30 d. The value has a positive correlation with coal rank. A great number of experimental data show that temperature, coal dimension and shape, coal rank, ash content, gas content, cleat, sediment environment, and coal style are the main factors affecting desorption time. According to the numerical simulation result, coal desorption volume affects the single well production. And the single well output has a positive correlation with the desorption. The variation of coal desorption time value can induce the change of output peak value of a single well and its occurrence time. [Copyright &y& Elsevier]

The current investigation is aimed to investigate the effect of new families of ionic liquid (IL) based surfactants for considering the enhanced oil recovery process. Imidazolium based ILs with chloride anion ([Cn mim][Cl]) with long alkyl chains, (n = 12 and 18) are synthesized and their effectiveness on the interfacial tension (IFT) and emulsification phenomena at the co-presence of NaCl and Na 2 SO 4 salts are examined. Dynamic IFT and critical micelle concentration (CMC) values of different solutions were measured and determined. Moreover, the performance of the considered solutions at the CMC was examined on the wettability alteration of the oil-wet carbonate rock surface. The obtained results revealed that for the shorter alkyl chain length IL (C12), the presence of NaCl was more effective compared with the Na 2 SO 4 while a reverse trend is observed for the longer alkyl chain length IL (C18). The contact angle measurement revealed that IL solutions containing sulfate anion altered the wettability of the oil-wet surface (from about 160°) toward the strongly water-wet state (41° for C12 and 45° for C18) and alkyl chain length introduces no significant effect. Besides, the solution containing chloride anion affected by IL type, that means longer alkyl chain length (C18) was unable to change wettability toward the water-wet state and wettability changed to 113° while C12 changed wettability to 34°. It is also found that although increasing the concentration of both ILs led to the lower IFT values with the minimum value of 0.6 mN/m, raising the temperature from 298 K to 348 K increased the IFT values. • Wettability and IFT of long-chain imidazolium based ionic liquids (ILs)/crude oil are studied. • Performance of Cl− and SO 4 2− on the surface activity of ILs is investigated. • Alkyl chain length and temperature effects on IFT, relaxation time and micellization are also examined. • It is fond that the wettability, IFT and CMC point depends on salt type and IL alkyl chain length. [ABSTRACT FROM AUTHOR]

An experimental and theoretical study is performed for bulk separation of H/CO mixture (70/30 volume %) by PSA process with zeolite 5A, a process widely used commercially in conjunction with the catalytic steam reforming of natural gas or naphtha. For the optimized adsorption conditions of PSA, the characteristics of adsorption/desorption characteristics have been studied through breakthrough and desorption experiments under various conditions. The purge-to-feed ratio is important to the H product purity only at a long adsorption step time. H could be concentrated from 70% in the feed to 99.99% at H recovery of 67.5%. The results of all five steps in PSA are successfully predicted by the LDF model considering an energy balance and nonlinear isotherm. For the model, the effective diffusivities (D,) are obtained separately from the uptake curves of H and CO. The Langmuir-Freundlich isotherm is used to correlate the experimental equilibrium data and is very well fitted to the results. [ABSTRACT FROM AUTHOR]

Since the Chernobyl and the Fukushima Daiichi disasters, contamination caused by radioactive accidents has attracted increasing attention. The present study evaluated immediate cleanup of 137Cs dissolved in surface water reservoir using an illite adsorbent, simulating an event of 137Cs contamination at Lake Paldang, South Korea. The study was conducted in two parts: (1) calculation of the residence time (t r) of illite adsorbent, and (2) evaluation of the adsorption time (t a) of illite adsorbent. t r was calculated based on physical properties (e.g., density, diameter, shape, and roughness) of the illite adsorbent at designated depth of surface water. Subsequently, t a was measured for 4 illite adsorbents (Korea01-Illite, Korea02-Illite, USA-Illite, and China-Illite) at 100 and 100,000 μg/L Cs, via kinetic adsorption experiment. Upon spraying of illite adsorbents with 50–150 μm diameter to locations where lake depth was between 6.5 m and 25.5 m, t r ranged from 0.132 to 3.300 h t a of 4 illite adsorbents was shorter than 0.6 and 2.5 h, for respective tests using 100 and 100,000 μg/L Cs. Based on the two characteristic times (t r and t a), the optimal particle diameter for the 4 illite adsorbents were evaluated at available lake depths in Lake Paldang. The study revealed that the USA-Illite is the efficient adsorbent at 100 μg/L Cs; in contrast, China-Illite could serve as the effective adsorbent at 100,000 μg/L Cs. Also, it was suggested that adsorbent efficiency had seasonal variations; t r was 2 h longer in winter than summer. In general, the study suggests that in the event of 137Cs contamination at Lake Paldang, Korea01-Illite is likely the best adsorbent to remove 137Cs due to its removal efficiency and accessibility from the illite deposit in Korea. • Decontamination of dissolved 137Cs using illite mineral adsorbents. • Removal of dissolved 137Cs considering physical and chemical behavior of adsorbent. • Influence of adsorbents' physical parameters on its settling velocity. • Optimal adsorbent size according to adsorbent sample, lake depth, and temperature. [ABSTRACT FROM AUTHOR]

Abstract: Dye-sensitized solar cells (DSCs) have been expected to be an alternative to the conventional silicon solar cell because of its advantages such as simple fabrication process, low manufacturing costs, and various applications. The related researches have been conducted so far for the improvement of the efficiency. However, the adsorption process usually takes 24h and it may actually be responsible for deteriorative overall productivity. Therefore, in this study, we tried to investigate the optimal dye-adsorption time by analyzing the photovoltaic performance and the electrochemical impedance. If the adsorption time was insufficient, it was not enough for dye to adsorb on TiO2. And the current was increased with the increase in the adsorption time. However, the increase stopped after dye molecules covered with whole TiO2 surface. DSCs were fabricated under identical condition except for the adsorption time from 1 to 24h. The change in the outputs of DSCs was verified by the I–V characteristic curves and the electrochemical impedance spectroscopy. As a result, the output was proportion to the adsorption time before sufficient adsorption and the performance was saturated after that. The irradiated area was 0.25cm2 and the maximum efficiency was 6.98%. [ABSTRACT FROM AUTHOR]