Search

Low-potassium molybdenum products have a wide range of applications in electronics, medical and other fields, and ammonia leaching has a very important impact on the production of low-potassium molybdenum products. In order to better control the amount of potassium released in the ammonia leaching process to reduce the pressure of potassium reduction in the subsequent process, this paper analyzed the potassium release law and gave its kinetic model and control method by conducting a one-factor simulation experiment on the influencing factors of potassium release in the ammonia leaching process of molybdenum bakery sand. The results show that the temperature, solid-liquid ratio and molybdenum roasting sand grain size have great influence on the release of potassium, and the optimal conditions for ammonia leaching are: temperature 30 ℃, solid-liquid ratio 1:3, molybdenum roasting sand grain size ranging from 150~178 μm, and ammonia concentration of 20%. In addition, Ca element is more favorable for potassium removal in the ammonia leaching process, while Na element is not favorable for potassium removal in the ammonia leaching process. After slaked lime has a certain effect on potassium removal in water leaching, the effect of sodium carbonate on potassium removal in water leaching is not obvious, so the addition of slaked lime in molybdenum roasted sand water leaching process is favorable to the production of low-potassium ammonium molybdate. Molybdenum roasted sand ammonia leaching process in the early stage of potassium release speed is faster, and the late stage of the speed becomes slower, the Avrami equation can be obtained to better simulate the process of potassium release in the early stage and late stage of ammonia leaching, and the kinetic equation of the ammonia leaching process was determined. [ABSTRACT FROM AUTHOR]

In this study, the potassium adsorption for the purification of crude ammonium perrhenate solutions in the presence of various cheap and available ion exchange resins is reported for the first time. After the resin screening test, the optimum resin (Purolite® C100 resin as a strong acid cation ion exchange resin in the sodium form) was selected for morphological analysis using field emission scanning electron microscopy, which was further examined by energy-dispersive spectroscopy. Moreover, X-ray elemental mapping of the surface of C100 resin revealed homogeneous potassium adsorption. BET and TGA tests confirmed the adsorbed potassium on the C100 resin. Among the isotherm models, the Langmuir isotherm provided the best fit according to the correlation coefficients. The adsorption parameters have been scrutinized, including contact time, initial potassium concentration, temperature, and competitive binary potassium and sodium adsorption. The result of the binary system exhibited a decrease in the potassium adsorption capacity of the resin in the presence of secondary ions due to competition for adsorption sites. Kinetic characteristics of the potassium adsorption process were investigated by pseudo-first-order and pseudo-second-order, intraparticle diffusion, and Elovich models. The adsorption process has been found to match the pseudo-first-order reaction. The continuous/extended experiments and the elution test were also evaluated. [ABSTRACT FROM AUTHOR]

Oil palm empty fruit bunch (EFB), a rich of polysaccharide and element as potassium, is being recognized as one of the most potential kinds of lignocellulosic biomass for bioenergy and biochemical production. In this study, EFB was subjected to hydrothermal pretreatment in the absence (HT) and presence of a sulfonated bentonite catalyst (HTcat). The effect of pretreatment on enzymatic hydrolysis and anaerobic digestion was investigated. The hydrothermal pretreatments were conducted at 160–200 °C for 5–25 min, while the effect of catalytic HTcat pretreatment of EFB was studied at 180–200 °C for 25 min. The results showed that temperature and catalyst in HTcat pretreatment were the main factors that could enhance both production of glucose and biohydrogen up to 1.04–1.14- and 3.32–4.36-fold, respectively, compared with those pretreated by HT at 180–200 °C for 25 min without catalyst. The catalyst specifically enhanced hemicellulose and lignin removal from EFB. During HT pretreatment, disruption of EFB cell wall also facilitated over 70% potassium dissolution from EFB to the liquid residue at 160–190 °C for 25 min, while poorer dissolution of potassium was found at 200 °C without or with catalyst addition. The HT pretreatment successfully improved the removal of potassium from EFB and its bioconversion yield. However, the potassium forms a sticky compound with other elements and soluble organic compound, and further study is required for the valorization of the potassium and liquid residue. [ABSTRACT FROM AUTHOR]

Cardiac dysrhythmia and sudden death account for a large proportion of cardiac mortality in dialysis patients. Risk factors for sudden death that are specific to dialysis patients include fluid and electrolyte imbalances during hemodialysis, particularly those of potassium. The risk of arrhythmia may be related to changes in serum K+ concentration during dialysis, and thus close attention should be paid to the dialysate K+ concentration and the serum–dialysate concentration gradient. Potassium profiling is a technique where the dialysate K+ concentration is gradually reduced to keep the gradient between blood and dialysate at a non-fluctuating low level. We provide a review of studies that compare constant potassium concentration in dialysate to gradual reduction in dialysate potassium concentration. These studies illustrate that adequate and more gradual potassium removal can be achieved with potassium profiling techniques, while having lower cardiac irritability.

Successive columns of gravel, fine sand, and mixture of acidified cotton and zeolite clinoptilolite nanoparticles (ZNP) were found efficient in olive mill waste water (OMW) treatment and desalination. The treatment decreased OMW’s salinity from 10.9 to 1.6 dSm−1 due to K+ removal. Furthermore, most total phenol contents were removed. The adsorption of K+ (aqueous solution) onto normal zeolite particles (NSP) and ZNP indicated that the pseudo-second order kinetic model is best model for K+ adsorption. Langmuir model was best fit model for K+ adsorption equilibrium. K+ maximum adsorption capacities were 7.2 and 16.5 mgg−1 for NSP and ZNP, respectively. [ABSTRACT FROM AUTHOR]

"Best agricultural practices for sustainable crop nutrition in Bulgaria" was the topic of an extensive research project supported by International Plant Nutrition Institute (IPNI) during the period 2009-2012. Omission plot trials (control, N, P, K, NP, NK, PK, NPK) were arranged in field, vegetable, fruit crops and wine grapes. Wheat (variety Aglika) and barley (variety Aheloy) were tested in crop rotation on four locations. The paper presents the P and K removal data under two representative for the tested crops conditions of South Bulgaria - Pomorie (Burgas region) and Sadievo (Stara Zagora region). P-removal was more influenced by the factor fertilization and for both wheat and barley was lower under conditions of balanced nutrition (NPK) - 6.0 - 7.0 kg.t-1 depending on the site. These lower rates were due to the higher yields obtained under balanced fertilization. K-removal was less influenced by the factor fertilization. Its value was lower for Sadievo - 15.0 kg.t-1 for both crops and higher for Pomorie - 17.5 kg.t-1 for wheat and 22.3 kg.t-1 for barley. The differences occurred in the K-removal values were due to the different level of the exchangeable potassium in the soil. In general both P and K-removal were more influenced by the site specificity and the climate conditions of the year than the nutrition regime. [ABSTRACT FROM AUTHOR]

A potassium-rich diet has several cardiovascular and renal health benefits; however, it is not recommended for patients with advanced chronic kidney disease or end-stage kidney disease because of the risk of life-threatening hyperkalemia. To assess the strength of evidence supporting potassium intake restriction in chronic kidney disease, the medical literature was searched looking for the current recommended approach and for evidence in support for such an approach. There is a lack of strong evidence supporting intense restriction of dietary potassium intake. There are several ways to reduce potassium intake without depriving the patient from fruits and vegetables, such as identifying hidden sources of potassium (processed food and preservatives) and soaking or boiling food to remove potassium. An individualized and gradual reduction of dietary potassium intake in people at risk of hyperkalemia is recommended. The current potassium dietary advice in chronic kidney disease needs to be reevaluated, individualized, and gradually introduced., Competing Interests: Conflict-of-interest statement: There are no conflicts of interest to report., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

The Na+-K+-ATPase and the ERK1/2 pathway appear to be linked in some fashion in a variety of cells. The Na+-K+-ATPase inhibitor ouabain can promote ERK1/2 activation. This activation involves Src, intracellular Ca2+ concentration ([2+]i) elevation, reactive oxygen species (ROS) generation, and EGF receptor (EGFR) transactivation. In contrast, ERK 1/2 can mediate changes in Na+-K+-ATPase activity and/or expression. Thus signaling between ERK1/2 and Na+-K+-ATPase can occur from either direction. Whether such bidirectionality can occur within the same cell has not been reported. In the present study, we have demonstrated that while ouabain (1 mM) produces only a small (-∼50%) increase in ERK1/2 phosphorylation in freshly isolated rat salivary (parotid acinar) epithelial cells, it potentiates the phosphorylation of ERK1/2 by submaximal concentrations of carbachol, a muscarinic receptor ligand that initiates fluid secretion. Although ERK1/2 is only modestly phosphorylated when cells are exposed to 1 mM ouabain or 10-6 M carbachol, the combination of these agents promotes ERK1/2 phosphorylation to near-maximal levels achieved by a log order carbachol concentration. These effects of ouabain are distinct from Na+-K+-ATPase inhibition by lowering extracellular K+, which promotes a rapid and large increase in ERK1/2 phosphor- ylation. ERK1/2 potentiation by ouabain (EC50 ∼100 μM) involves PKC, Src, and alterations in [Ca2+]i but not ROS generation or EGFR transactivation. In addition, inhibition of ERK1/2 reduces Na2+K+- ATPase activity (measured as stimulation of QO2 by carbachol and the cationophore nystatin). These results suggest that ERK1/2 and Na+- K+-ATPase may signal to each other in each direction under defined conditions in a single cell type. [ABSTRACT FROM AUTHOR]

Patients on chronic hemodialysis often portray high serum [K+]. Although dietary excesses are evident in many cases, in others, the cause of hyperkalemia cannot be identified. In such cases, hyperkalemia could result from decreased potassium removal during dialysis. This situation could occur if alkalinization of body fluids during dialysis would drive potassium into the cell, thus decreasing the potassium gradient across the dialysis membrane. In 35 chronic hemodialysis patients, we compared two dialysis sessions performed 7 days apart. Bicarbonate or acetate as dialysate buffers were randomly assigned for the first dialysis. The buffer was switched for the second dialysis. Serum [K+], [HCO3–], and pH were measured in samples drawn before dialysis; 60, 120, 180, and 240 min into dialysis; and 60 and 90 min after dialysis. The potassium removed was measured in the dialysate. During the first 2 hr, serum [K+] decreased equally with both types of dialysates but declined more during the last 2 hr with bicarbonate dialysis. After dialysis, the serum [K+] rebounded higher with bicarbonate bringing the serum [K+] up to par with acetate. The lower serum [K+] through the second half of bicarbonate dialysis did not impair potassium removal (295.9 ± 9.6 mmol with bicarbonate and 299.0 ± 14.4 mmol with acetate). The measured serum K+ concentrations correlated with serum [HCO3–] and blood pH during bicarbonate dialysis but not during acetate dialysis. Alkalinization induced by bicarbonate administration may cause redistribution of K during bicarbonate dialysis but this does not impair its removal. The more marked lowering of potassium during bicarbonate dialysis occurs late in dialysis, when exchange is negligible because of a low gradient. [ABSTRACT FROM AUTHOR]

Background. The influence of potassium (K) removal on dialysis efficiency as measured by urea elimination is not clear. In this prospective, randomized, cross‐over study we investigated the magnitude of K removal and its effect on urea (u) elimination during high‐flux haemodialysis (HD). [ABSTRACT FROM PUBLISHER]