This study focuses on CO_(2) capture by pressure swing adsorption(PSA),with modified clinoptilolite as the adsorbent.Natural clinoptilolite is modified by roasting,by acid pickling,by a combination of acid pickling an...This study focuses on CO_(2) capture by pressure swing adsorption(PSA),with modified clinoptilolite as the adsorbent.Natural clinoptilolite is modified by roasting,by acid pickling,by a combination of acid pickling and roasting,and by ion exchange.Modification by acid pickling-roasting and by ion exchange are found to give the highest CO_(2) adsorption capacities,of 730 mL/g and 876.7 mL/g,respectively.It is found that regeneration of clinoptilolite by a combination of vacuum desorption and heating enables recovery of as much as 89%of its previous CO_(2) adsorption capacity.To examine the CO_(2) adsorption capacity of clinoptilolite when applied to mixed gas,a simulated coking exhaust containing 12%CO_(2) and 4%O_(2) is used,and it is found that ion exchange modified clinoptilolite achieves a CO_(2) removal efficiency of 92.5%.A BET test reveals that acid pickling-roasting and Na^(+) modification enhance the porosity of clinoptilolite,thereby improving its adsorption capacity.This work demonstrates the feasibility of applying modified clinoptilolite as an effective adsorbent for COO_(2)capture,providing a promising tool for dealing with greenhouse gases.展开更多
The influences of roasting activation on the particle morphology, microscopic structure, and adsorption properties of natural clinoptilolites were investigated. The experimental results show that the optimal modified ...The influences of roasting activation on the particle morphology, microscopic structure, and adsorption properties of natural clinoptilolites were investigated. The experimental results show that the optimal modified conditions include a calcination temperature at 400 ℃, a roasting time of 0.5 h, and furnace cooling. The ammonia nitrogen removal rate from analog renewable water of the modified clinoptilolites reached 72% in the optimized conditions, which is 12% higher than that of natural ones. Scanning electron microscopy analysis showed that the surface morphology changed, the micro-hole size increased, and the surface became smoother and more uniform after calcination. The single-point total adsorption average pore width increased from 7.74 nm to 10.64 nm.展开更多
Ammonium can change the type of natural clinoptilolite from Jinyun ofZhejiang Province of China. The character of exchange and selectivity of ammonium type clinoptilolite to the alkali and alkaline - earth metal were ...Ammonium can change the type of natural clinoptilolite from Jinyun ofZhejiang Province of China. The character of exchange and selectivity of ammonium type clinoptilolite to the alkali and alkaline - earth metal were investigated, the heatresistance and nitric acid - resistance of natural clinoptilolitewere discussed. All types of clinoptilolite were researched by means of X - ray,IR spectroscopy, DTA analyses. The ion exchange was experimented by columnoperation, indicating that the valid amount of exchange capacity of NH+4 typeclinoptilolite is more than 25mg/g.展开更多
In this article one of the advanced oxidation processes (AOP) combined methods, photocatalyst /H2O2, is utilized in order to study photodegradation of ethylene dichloride (EDC) in water. Nano Titanium (IV) Oxide, supp...In this article one of the advanced oxidation processes (AOP) combined methods, photocatalyst /H2O2, is utilized in order to study photodegradation of ethylene dichloride (EDC) in water. Nano Titanium (IV) Oxide, supported on Clinoptilolite (CP) (Iranian natural zeolite) using solid-state dispersion (SSD) method for improvement of its photocatalytic properties. The results show that the TiO2/Clinoptilolite (SSD) is an active photocatalyst. The effects of five important photocatalytic reaction parameters including the initial concentration of ethylene dichloride, the ratio of TiO2/Clinoptilolite, the catalyst concentration, H2O2 concentration and pH in photodegradation of ethylene dichloride were examined. In this experiments, the design and also the optimum parameters were obtained by Taguchi Method, using Design Expert8®software. Taguchi's L27 (5^3) orthogonal array design was employed for the experimental plan. Four parameters were found to be significant whereas, pH was found to be an insignificant parameter after conducting experiments. A first order reaction with K = 0.007 min-1 was observed for the photocatalytic degradation reaction.展开更多
BACKGROUND Irritable bowel syndrome(IBS)is a highly prevalent gastrointestinal disorder with poor response to treatment.IBS with predominant diarrhea(IBS-D)is accompanied by abdominal pain as well as high stool freque...BACKGROUND Irritable bowel syndrome(IBS)is a highly prevalent gastrointestinal disorder with poor response to treatment.IBS with predominant diarrhea(IBS-D)is accompanied by abdominal pain as well as high stool frequency and urgency.Purified clinoptilolite-tuff(PCT),which is approved by the Food and Drug Administration for use as a dietary supplement with the brand name G-PUR®,has previously shown therapeutic potential in other indications based on its physical adsorption capacity.AIM To assess whether symptoms of IBS-D can be ameliorated by oral treatment with PCT.METHODS In this randomized,placebo-controlled,double-blind pilot study,30 patients with IBS-D diagnosis based on Rome IV criteria were enrolled.Following a 4-wk run-in phase,14 patients were randomized to receive a 12-wk treatment with G-PUR®(2 g three times daily),and 16 patients received placebo.The relief from IBS-D symptoms as measured by the proportion of responders according to the Subject’s Global Assessment(SGA)of Relief was assessed as the primary outcome.For the secondary outcomes,validated IBS-D associated symptom questionnaires,exploratory biomarkers and microbiome data were collected.RESULTS The proportions of SGA of Relief responders after 12 wk were comparable in both groups,namely 21%in the G-PUR®group and 25%in the placebo group.After 4 wk of treatment,36%of patients in the G-PUR®group vs 0%in the placebo group reported complete or considerable relief.An improvement in daily abdominal pain was noted in 94%vs 83%(P=0.0353),and the median number of days with diarrhea per week decreased by 2.4 d vs 0.3 d in the G-PUR®and placebo groups,respectively.Positive trends were observed for 50%of responders in the Bristol Stool Form Scale.Positive trends were also noted for combined abdominal pain and stool consistency response and the Perceived Stress Questionnaire score.Only 64%in the G-PUR®group compared to 86%in the placebo group required rescue medication intake during the study.Stool microbiome studies showed a minor increase in diversity in the G-PUR®group but not in the placebo group.No PCT-related serious adverse events were reported.CONCLUSION In this randomized,double-blind,placebo-controlled study,the PCT product,G-PUR®,demonstrated safety and clinical benefit towards some symptoms of IBS-D,representing a promising novel treatment option for these patients.展开更多
CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using t...CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using the αs-plots method. The high resolution αs-plots show that the isotherms are divided into four parts corresponding to adsorption in ultramicropores, intersections, supermicropores and external surface area, respectively. The mineralogies of natural zeolites are determined by X-ray analysis. N： low-pressure hysteresis loops, displayed by some substrata, are related to the micropore structure and to the ion-exchange treatment at which the natural precursors were subjected. The adsorption behavior of these substrata was examined in the range of relative pressures between 10^-5-1. Natural samples were used as reference materials to carry out the sorption analyses of the dealuminated samples. The effect of narrow micropore constrictions on the adsorption behavior of clinoptilolites was explored. The occurrence of a low-pressure hysteresis loop on the sorption isotherm of a modified sample is associated to the strong adsorption of the adsorbate molecules at the entrance of the necked-shape micropores, which interfere with the diffusion of the adsorbate molecules inside the porous structure.展开更多
Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealumin...Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealuminated clinoptilolite zeolites （CLIDA1-CLIDA5） were conditioned by means of acid treatment of the natural zeolitic precursor （CLINA） with HCI at different concentration. Adsorption of selected gases （N2 and 02） on clinoptilolite zeolites were studied in the temperature range from 398 K to 498 K. The Langmuir adsorption model was found to approximately fit the gases adsorption data, within the selected temperature range. The uptake amount of these gases by the diverse adsorbents was temperature dependent. Additionally, the energies of interaction between of these gases with clinoptilolite microporous walls were realized from the evaluation of the isosteric heats of adsorption （qst）. These isosteric heats were found to obey in the following decreasing order： qst （N2）： CLIDA1 〉 CLIDA3 〉 CLIDA2 〉 CLIDA4 〉 CLIDA5 〉 CLINA; while qst （02）： CLIDA3 〉 CLIDA2 〉 CL1DA1 〉 CLIDA5 〉 CLIDA4 〉 CLINA.展开更多
Maize forage is poor in protein content which leads to low quality and nutritive value.Regarding the high feed costs of protein supplementations,legumes can be used in livestock nutrition for their high protein conten...Maize forage is poor in protein content which leads to low quality and nutritive value.Regarding the high feed costs of protein supplementations,legumes can be used in livestock nutrition for their high protein content,and thus,provide cost savings.In this study,maize(Zea mays L.)and cowpea(Vigna unguiculata L.)were intercropped in different sowing densities and fertilization with clinoptilolite and their monocropping equivalents were tested to determine the best intercropping system on forage yield and quality.Maize was cultivated alone(75,000 plants·ha^-1)and intercropped with cowpea as follows:75,000 plants·ha-1 of maize and 37,500 plants·ha^-1 of cowpea(MC1),75,000 plants·ha^-1 of maize and 50,000 plants·ha-1 of cowpea(MC2)and 75,000 plants·ha^-1 of maize and 75,000 plants·ha^-1 of cowpea(MC3),in rows alternating with maize.The highest dry matter yield was produced by MC3(23.8 t·ha^-1),and the lowest by SM(20.7 t·ha^-1)in fertilization with clinoptilolite.All intercropped systems had higher crude protein contents,MC1(101 g·kg^-1 DM),MC2(108 g·kg^-1 DM)and MC3(117 g·kg^-1 DM),than the monocrop maize(84 g·kg^-1 DM)in fertilization with clinoptilolite.Intercropping of maize with cowpea and fertilization with clinoptilolite reduced neutral detergent fiber,resulting in increased forage digestibility.Therefore,maize intercropping with cowpea and fertilization with clinoptilolite could substantially increase forage quantity and quality,and decrease requirements for protein supplements as compared with maize monocrop.展开更多
The shortages of chemical fertilizers in Cuba in 90s caused the introduction of different research results obtained on this time for the implementation of natural zeolites in the fertilizer industry. It＇s known as th...The shortages of chemical fertilizers in Cuba in 90s caused the introduction of different research results obtained on this time for the implementation of natural zeolites in the fertilizer industry. It＇s known as the high capacity of cation exchange of the natural Cuban clinoptilolite, which contributes to reducing nutrient losses, such as ammonia, and keeping the potassium and phosphorus cations available. Extensive tests were done on the field with the objective to evaluate the agronomic effect of incorporating this mineral in fertilizer. The results obtained in this experiment contributed to almost all Cuban chemical fertilizers, which has been incorporated around 15%-20% of natural zeolite clinoptilolite in its composition by Cuban agriculture consumes, reducing the chemical carriers of the fertilizers and decreasing the contamination of the environment. Also this mineral contributes for increases in agricultural income more than 15% in all cases; additionally, a trend can be observed towards gradual recovery of some soil fertility indicators, in which the chemical fertilizers with Fertcel was applied.展开更多
The present study examined the adsorption of silver ion in aqueous solution onto natural clinoptilolite zeolite from Futatsui Mine, Akita Prefecture, Japan. The effects of various parameters, i.e., solution pH, adsorb...The present study examined the adsorption of silver ion in aqueous solution onto natural clinoptilolite zeolite from Futatsui Mine, Akita Prefecture, Japan. The effects of various parameters, i.e., solution pH, adsorbent dosage, adsorption time, silver ion solution concentration, and temperature, on silver ion adsorption process onto clinoptilolite were examined. Additionally, the thermodynamics of the silver ion adsorption process was investigated. The optimum pH for silver adsorption was determined to be around 4.0. The adsorption process could be well described by the Langmuir isotherm model. The calculated maximum adsorption capacity was 0.64 mmol/g. Adsorption kinetics studies were also conducted. The results showed that the adsorption process preferentially followed the pseudo-second-order kinetics model over the pseudo-first-order model. Furthermore, with decreasing aqueous solution temperatures, the adsorption kinetics became slower and the amount of silver ion adsorbed increased. The thermodynamic values, ΔG<sup>0</sup>, ΔH<sup>0</sup>, and ΔS<sup>0</sup>, indicated that adsorption was an exo-thermic and spontaneous process.展开更多
基金supported by the Natural Science Foundation of China(42177359)the Open Fund of the National Engineering Laboratory for Site Remediation Technologies(NEL-SRT201907).
文摘This study focuses on CO_(2) capture by pressure swing adsorption(PSA),with modified clinoptilolite as the adsorbent.Natural clinoptilolite is modified by roasting,by acid pickling,by a combination of acid pickling and roasting,and by ion exchange.Modification by acid pickling-roasting and by ion exchange are found to give the highest CO_(2) adsorption capacities,of 730 mL/g and 876.7 mL/g,respectively.It is found that regeneration of clinoptilolite by a combination of vacuum desorption and heating enables recovery of as much as 89%of its previous CO_(2) adsorption capacity.To examine the CO_(2) adsorption capacity of clinoptilolite when applied to mixed gas,a simulated coking exhaust containing 12%CO_(2) and 4%O_(2) is used,and it is found that ion exchange modified clinoptilolite achieves a CO_(2) removal efficiency of 92.5%.A BET test reveals that acid pickling-roasting and Na^(+) modification enhance the porosity of clinoptilolite,thereby improving its adsorption capacity.This work demonstrates the feasibility of applying modified clinoptilolite as an effective adsorbent for COO_(2)capture,providing a promising tool for dealing with greenhouse gases.
基金Funded by the National Natural Science Foundation of China(No.51174017)
文摘The influences of roasting activation on the particle morphology, microscopic structure, and adsorption properties of natural clinoptilolites were investigated. The experimental results show that the optimal modified conditions include a calcination temperature at 400 ℃, a roasting time of 0.5 h, and furnace cooling. The ammonia nitrogen removal rate from analog renewable water of the modified clinoptilolites reached 72% in the optimized conditions, which is 12% higher than that of natural ones. Scanning electron microscopy analysis showed that the surface morphology changed, the micro-hole size increased, and the surface became smoother and more uniform after calcination. The single-point total adsorption average pore width increased from 7.74 nm to 10.64 nm.
文摘Ammonium can change the type of natural clinoptilolite from Jinyun ofZhejiang Province of China. The character of exchange and selectivity of ammonium type clinoptilolite to the alkali and alkaline - earth metal were investigated, the heatresistance and nitric acid - resistance of natural clinoptilolitewere discussed. All types of clinoptilolite were researched by means of X - ray,IR spectroscopy, DTA analyses. The ion exchange was experimented by columnoperation, indicating that the valid amount of exchange capacity of NH+4 typeclinoptilolite is more than 25mg/g.
文摘In this article one of the advanced oxidation processes (AOP) combined methods, photocatalyst /H2O2, is utilized in order to study photodegradation of ethylene dichloride (EDC) in water. Nano Titanium (IV) Oxide, supported on Clinoptilolite (CP) (Iranian natural zeolite) using solid-state dispersion (SSD) method for improvement of its photocatalytic properties. The results show that the TiO2/Clinoptilolite (SSD) is an active photocatalyst. The effects of five important photocatalytic reaction parameters including the initial concentration of ethylene dichloride, the ratio of TiO2/Clinoptilolite, the catalyst concentration, H2O2 concentration and pH in photodegradation of ethylene dichloride were examined. In this experiments, the design and also the optimum parameters were obtained by Taguchi Method, using Design Expert8®software. Taguchi's L27 (5^3) orthogonal array design was employed for the experimental plan. Four parameters were found to be significant whereas, pH was found to be an insignificant parameter after conducting experiments. A first order reaction with K = 0.007 min-1 was observed for the photocatalytic degradation reaction.
基金We thank myBioma GmbH for the microbiome analyses and designing the corresponding figures for the manuscript.
文摘BACKGROUND Irritable bowel syndrome(IBS)is a highly prevalent gastrointestinal disorder with poor response to treatment.IBS with predominant diarrhea(IBS-D)is accompanied by abdominal pain as well as high stool frequency and urgency.Purified clinoptilolite-tuff(PCT),which is approved by the Food and Drug Administration for use as a dietary supplement with the brand name G-PUR®,has previously shown therapeutic potential in other indications based on its physical adsorption capacity.AIM To assess whether symptoms of IBS-D can be ameliorated by oral treatment with PCT.METHODS In this randomized,placebo-controlled,double-blind pilot study,30 patients with IBS-D diagnosis based on Rome IV criteria were enrolled.Following a 4-wk run-in phase,14 patients were randomized to receive a 12-wk treatment with G-PUR®(2 g three times daily),and 16 patients received placebo.The relief from IBS-D symptoms as measured by the proportion of responders according to the Subject’s Global Assessment(SGA)of Relief was assessed as the primary outcome.For the secondary outcomes,validated IBS-D associated symptom questionnaires,exploratory biomarkers and microbiome data were collected.RESULTS The proportions of SGA of Relief responders after 12 wk were comparable in both groups,namely 21%in the G-PUR®group and 25%in the placebo group.After 4 wk of treatment,36%of patients in the G-PUR®group vs 0%in the placebo group reported complete or considerable relief.An improvement in daily abdominal pain was noted in 94%vs 83%(P=0.0353),and the median number of days with diarrhea per week decreased by 2.4 d vs 0.3 d in the G-PUR®and placebo groups,respectively.Positive trends were observed for 50%of responders in the Bristol Stool Form Scale.Positive trends were also noted for combined abdominal pain and stool consistency response and the Perceived Stress Questionnaire score.Only 64%in the G-PUR®group compared to 86%in the placebo group required rescue medication intake during the study.Stool microbiome studies showed a minor increase in diversity in the G-PUR®group but not in the placebo group.No PCT-related serious adverse events were reported.CONCLUSION In this randomized,double-blind,placebo-controlled study,the PCT product,G-PUR®,demonstrated safety and clinical benefit towards some symptoms of IBS-D,representing a promising novel treatment option for these patients.
文摘CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using the αs-plots method. The high resolution αs-plots show that the isotherms are divided into four parts corresponding to adsorption in ultramicropores, intersections, supermicropores and external surface area, respectively. The mineralogies of natural zeolites are determined by X-ray analysis. N： low-pressure hysteresis loops, displayed by some substrata, are related to the micropore structure and to the ion-exchange treatment at which the natural precursors were subjected. The adsorption behavior of these substrata was examined in the range of relative pressures between 10^-5-1. Natural samples were used as reference materials to carry out the sorption analyses of the dealuminated samples. The effect of narrow micropore constrictions on the adsorption behavior of clinoptilolites was explored. The occurrence of a low-pressure hysteresis loop on the sorption isotherm of a modified sample is associated to the strong adsorption of the adsorbate molecules at the entrance of the necked-shape micropores, which interfere with the diffusion of the adsorbate molecules inside the porous structure.
文摘Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealuminated clinoptilolite zeolites （CLIDA1-CLIDA5） were conditioned by means of acid treatment of the natural zeolitic precursor （CLINA） with HCI at different concentration. Adsorption of selected gases （N2 and 02） on clinoptilolite zeolites were studied in the temperature range from 398 K to 498 K. The Langmuir adsorption model was found to approximately fit the gases adsorption data, within the selected temperature range. The uptake amount of these gases by the diverse adsorbents was temperature dependent. Additionally, the energies of interaction between of these gases with clinoptilolite microporous walls were realized from the evaluation of the isosteric heats of adsorption （qst）. These isosteric heats were found to obey in the following decreasing order： qst （N2）： CLIDA1 〉 CLIDA3 〉 CLIDA2 〉 CLIDA4 〉 CLIDA5 〉 CLINA; while qst （02）： CLIDA3 〉 CLIDA2 〉 CL1DA1 〉 CLIDA5 〉 CLIDA4 〉 CLINA.
文摘Maize forage is poor in protein content which leads to low quality and nutritive value.Regarding the high feed costs of protein supplementations,legumes can be used in livestock nutrition for their high protein content,and thus,provide cost savings.In this study,maize(Zea mays L.)and cowpea(Vigna unguiculata L.)were intercropped in different sowing densities and fertilization with clinoptilolite and their monocropping equivalents were tested to determine the best intercropping system on forage yield and quality.Maize was cultivated alone(75,000 plants·ha^-1)and intercropped with cowpea as follows:75,000 plants·ha-1 of maize and 37,500 plants·ha^-1 of cowpea(MC1),75,000 plants·ha^-1 of maize and 50,000 plants·ha-1 of cowpea(MC2)and 75,000 plants·ha^-1 of maize and 75,000 plants·ha^-1 of cowpea(MC3),in rows alternating with maize.The highest dry matter yield was produced by MC3(23.8 t·ha^-1),and the lowest by SM(20.7 t·ha^-1)in fertilization with clinoptilolite.All intercropped systems had higher crude protein contents,MC1(101 g·kg^-1 DM),MC2(108 g·kg^-1 DM)and MC3(117 g·kg^-1 DM),than the monocrop maize(84 g·kg^-1 DM)in fertilization with clinoptilolite.Intercropping of maize with cowpea and fertilization with clinoptilolite reduced neutral detergent fiber,resulting in increased forage digestibility.Therefore,maize intercropping with cowpea and fertilization with clinoptilolite could substantially increase forage quantity and quality,and decrease requirements for protein supplements as compared with maize monocrop.
文摘The shortages of chemical fertilizers in Cuba in 90s caused the introduction of different research results obtained on this time for the implementation of natural zeolites in the fertilizer industry. It＇s known as the high capacity of cation exchange of the natural Cuban clinoptilolite, which contributes to reducing nutrient losses, such as ammonia, and keeping the potassium and phosphorus cations available. Extensive tests were done on the field with the objective to evaluate the agronomic effect of incorporating this mineral in fertilizer. The results obtained in this experiment contributed to almost all Cuban chemical fertilizers, which has been incorporated around 15%-20% of natural zeolite clinoptilolite in its composition by Cuban agriculture consumes, reducing the chemical carriers of the fertilizers and decreasing the contamination of the environment. Also this mineral contributes for increases in agricultural income more than 15% in all cases; additionally, a trend can be observed towards gradual recovery of some soil fertility indicators, in which the chemical fertilizers with Fertcel was applied.
文摘The present study examined the adsorption of silver ion in aqueous solution onto natural clinoptilolite zeolite from Futatsui Mine, Akita Prefecture, Japan. The effects of various parameters, i.e., solution pH, adsorbent dosage, adsorption time, silver ion solution concentration, and temperature, on silver ion adsorption process onto clinoptilolite were examined. Additionally, the thermodynamics of the silver ion adsorption process was investigated. The optimum pH for silver adsorption was determined to be around 4.0. The adsorption process could be well described by the Langmuir isotherm model. The calculated maximum adsorption capacity was 0.64 mmol/g. Adsorption kinetics studies were also conducted. The results showed that the adsorption process preferentially followed the pseudo-second-order kinetics model over the pseudo-first-order model. Furthermore, with decreasing aqueous solution temperatures, the adsorption kinetics became slower and the amount of silver ion adsorbed increased. The thermodynamic values, ΔG<sup>0</sup>, ΔH<sup>0</sup>, and ΔS<sup>0</sup>, indicated that adsorption was an exo-thermic and spontaneous process.
