Alkaline Load Research Articles

Dietary Acid Load and Relationship with Diseases

The acid-base balance of the human body is influenced by the nutritional intake and dietary composition of individuals. It is of paramount importance to maintain this equilibrium for the optimal health of humans. The body receives acid or alkaline precursors from dietary intake. In general, the consumption of animal-based foods results in an acid load, whereas the consumption of plant-based foods contributes to an alkaline load. Diets high in dietary acid load cause a state of diet-induced metabolic acidosis, which is associated with the development of cardiometabolic diseases. The significance of dietary acid-base balance in the context of cardiometabolic diseases, which have emerged as a significant contributor to global morbidity, is now being acknowledged in the literature. The objective of this review is to examine the existing evidence concerning the relationship between dietary acid load and chronic diseases and metabolic disorders, as well as the potential mechanisms underlying their development. Keywords: Dietary acid load, non-communicable diseases, potential renal acid load, net endogenous acid production

Study on Soda–Ethanol Delignification of Pine Sawdust for a Biorefinery

The soda–ethanol process was conceived as a sulfur-free pulping process, which may also be an alternative to conventional alkaline pulping, such as kraft or soda–AQ in the biorefinery context. An in-depth study using two experimental designs was conducted to establish the viability of soda–ethanol delignification of pine sawdust. At first, a simple factorial design involving the ethanol–water ratio (ethanol:water) and the alkaline load (AL, % over dry wood, odw) was applied to define the levels of these variables and their eventual interaction. Then, a 32 experimental design was performed to evaluate the ability of the process concerning the pulping of pine sawdust. The tested conditions were carefully selected to screen a broad range of cooking times (60, 100, and 140 min) and alkaline loads (19.0, 23.3, and 27.6 %odw) to obtain pulps with different extents of delignification (residual lignin contents). Finally, the kraft, soda–AQ, and soda–ethanol treatments were compared. Soda–ethanol pulping was shown to be a suitable delignification stage for a biorefinery scheme of Pinus elliottii and Pinus taeda sawdust. It has many advantages over traditional processes regarding its environmental impact, harmless chemicals, and selectivity. The tested conditions were similar to those frequently used in conventional pulping at an industrial scale, suggesting the technical feasibility of the soda–ethanol process for pine sawdust processing.

MODELLING, SIMULATION AND OPTIMIZATION OF BIOETHANOL PRODUCTION FROM LIGNOCELLULOSE MATERIALS USING OPEN-SOURCE SOFTWARE- SCILAB, R AND AP MONITOR

Bioethanol production from lignocellulose biomass has gained a lot of traction over the last two decades because it is a viable alternative energy source to fossil fuel and does not compete with the food supply like first-generation bioethanol does. In this study, previously reported research is used to generate mathematical models for enzymatic hydrolysis, and co-fermentation operations, which are then improved to include the decomposition of hemicellulose to xylose sugars. Two case studies were investigated and modelled in the Scilab and R software which are free and open-source software for numerical and statistical computing, respectively. The first case study examined the impact of alkaline loading and temperature (represented by A & B respectively) on delignification. Results show that A and A² are significant model terms and the optimum process parameters for delignification of 61% are 0.8% alkaline loading and 121℃. The second case investigated how the simultaneous saccharification and co-fermentation (SSCF) operation responds to the key control variables namely cellulose loading(A), hemicellulose loading(B), enzyme loading (C), yeast loading (D), temperature (E) and time (F). From the analysis of variance, the variables found to be significant model terms are: cellulose loading (A), enzyme loading (C), time (F), and then AF, A², C², F². Major parameters of the SSCF unit are then optimized using the APMonitor modeling package in Python to give 0.1263kg/kg minimum enzyme adsorbed per substrate loading, maximum cellulose conversion as 26.26% and a 47.9% maximum ethanol yield. Keywords: bioethanol; optimize; simultaneous saccharification and co-fermentation; dynamic modelling

Bicarbonate transport of airway surface epithelia in luminally perfused mice bronchioles

HCO3− secretion in distal airways is critical for airway mucosal defense. HCO3−/H+ transport across the apical membrane of airway surface epithelial cells was studied by measuring intracellular pH in luminally microperfused freshly dissected mice bronchioles. Functional studies demonstrated that CFTR, ENaC, Cl−–HCO3− exchange, Na+-H+ exchange, and Na+–HCO3− cotransport are involved in apical HCO3−/H+ transport. RT-PCR of isolated bronchioles detected fragments from Cftr, α, β, γ subunits of ENaC, Ae2, Ae3, NBCe1, NBCe2, NBCn1, NDCBE, NBCn2, Nhe1, Nhe2, Nhe4, Nhe5, Slc26a4, Slc26a6, and Slc26a9. We assume that continuous decline of intracellular pH following alkaline load demonstrates time course of HCO3− secretion into the lumen which is perfused with a HCO3−-free solution. Forskolin-stimulated HCO3− secretion was substantially inhibited by luminal application of CFTRinh-172 (5 μM), H2DIDS (200 μM), and amiloride (1 μM). In bronchioles from a cystic fibrosis mouse model, basal and acetylcholine-stimulated HCO3− secretion was substantially impaired, but forskolin transiently accelerated HCO3− secretion of which the magnitude was comparable to wild-type bronchioles. In conclusion, we have characterized apical HCO3−/H+ transport in native bronchioles. We have demonstrated that cAMP-mediated and Ca2+-mediated pathways are involved in HCO3− secretion and that apical HCO3− secretion is largely mediated by CFTR and H2DIDS-sensitive Cl−–HCO3− exchanger, most likely Slc26a9. The impairment of HCO3− secretion in bronchioles from a cystic fibrosis mouse model may be related to the pathogenesis of early lung disease in cystic fibrosis.

The method of alkaline loading and its application in the clinic of internal diseases

The works of recent years have clearly shown the importance that the alkaline-acid balance has in the physiology and pathology of the animal organism. The desire to maintain this balance at a certain height occurs by coordinating the work of a number of organs: the lungs, secreting C02, the liver, taking part in the production of ammonia, the gastrointestinal tract, secerning acid and alkaline secretions and, finally, the kidneys, giving urine with a high acid content and someone's slit, then with less-take part in the regulation of alkalineacid balance. That is why, naturally, the study of the functions of various organs aimed at regulating and maintaining the alkaline-acid balance attracted the attention of clinicians. Rehn and Gnzburg, then Pannewitz, Popescu, Inotesti. Su11a, and finally Rosenberg and Hellfors, studying fluctuations in the concentration of hydrogen ions in urine after loading with alkalis and acids, sought to gain an idea of kidney function aimed at maintaining the gap.- acids. balance, and at the same time apply this method to the study of the functional state of the kidneys in general. However, it turned out to be insufficient to talk about this condition on the basis of determining the Ph of urine. The Ph fluctuations are not always sufficiently prominent, as the review of the data obtained by the authors shows, because the concentration of hydrogen ions is a value depending on the ratio of acid to alkali (voltage 002 and bicarbonate content). This forced us to put forward another method for determining changes in the functions of tissues and kidneys for the introduction of alkali: Mainzer et al., A. G e f t e r emphasized the importance of the determination of bicarbonates in urine and suggested using the method of their determination by gasometric method (according to van Slyke'y), while giving this definition a much greater value than the study of Ph fluctuations alone.

A novel catalyst prepared from black liquor for biodiesel conversion: An optimization study

This paper reports a new approach for high-value conversion of black liquor into biochar to catalyse the transesterification for biodiesel conversion using waste fry oil (WFO). The central composite design (CCD) and response surface methodology (RSM) were employed to optimize the biodiesel preparation using the catalyst prepared from the paper pulp black liquor precipitated biochar. The transesterification reaction is catalysed by oxidative functional groups (enolic) on the surface of biochar. The effect of alkaline loading in biochar, carbonization temperature, the methanol to oil ratio and the catalyst loading were systematically investigated. The optimal biodiesel conversion conditions were achieved as the following: 27wt% (alkaline loading in biochar), 585 °C (carbonization temperature), 7 (methanol to oil ratio) and 5.5 wt% (catalyst loading), with the biodiesel yield of 95%.

Relative impacts of global changes and regional watershed changes on the inorganic carbon balance of the Chesapeake Bay

Abstract. The Chesapeake Bay is a large coastal-plain estuary that has experienced considerable anthropogenic change over the past century. At the regional scale, land-use change has doubled the nutrient input from rivers and led to an increase in riverine carbon and alkalinity. The bay has also experienced global changes, including the rise of atmospheric temperature and CO2. Here we seek to understand the relative impact of these changes on the inorganic carbon balance of the bay between the early 1900s and the early 2000s. We use a linked land–estuarine–ocean modeling system that includes both inorganic and organic carbon and nitrogen cycling. Sensitivity experiments are performed to isolate the effect of changes in (1) atmospheric CO2, (2) temperature, (3) riverine nitrogen loading and (4) riverine carbon and alkalinity loading. Specifically, we find that over the past century global changes have increased ingassing by roughly the same amount (∼30 Gg-C yr−1) as has the increased riverine loadings. While the former is due primarily to increases in atmospheric CO2, the latter results from increased net ecosystem production that enhances ingassing. Interestingly, these increases in ingassing are partially mitigated by increased temperatures and increased riverine carbon and alkalinity inputs, both of which enhance outgassing. Overall, the bay has evolved over the century to take up more atmospheric CO2 and produce more organic carbon. These results suggest that over the past century, changes in riverine nutrient loads have played an important role in altering coastal carbon budgets, but that ongoing global changes have also substantially affected coastal carbonate chemistry.

Preparation of biochar catalyst from black liquor by spray drying and fluidized bed carbonation for biodiesel synthesis

Lab-scale experiments were carried out to investigate a new approach of preparing biochar-based catalyst for transesterification reaction. Black liquor (BL) from cotton pulping process was used as a precursor for preparing the catalyst via spray drying followed by fast carbonization in a fluidized bed reactor. Response surface methodology (RSM) was employed to statistically analyze and optimize the entire process of catalytic synthesis of biodiesel from a waste frying oil, consisted of the catalyst preparation and transesterification steps. Several major operation parameters of the biodiesel synthesis process, including alkaline loading in biochar, methanol to oil ratio, catalyst loading, and the carbonization temperature of catalyst, were studied for their effects on biodiesel conversion. The optimal condition for achieving the maximum biodiesel conversion (i.e. 91.5 %) was found to be: 27wt% alkaline loading in biochar, 600°C carbonization temperature, 7.7 methanol to oil ratio, and 6.5wt% catalyst loading. Overall, the spry drying fluidized bed carbonization demonstrated its viability for significantly reducing duration of high temperature carbonization, opening up the prospects of manufacturing the catalyst in a much less energy consumption manor.

Trabecular Meshwork TREK-1 Channels Function as Polymodal Integrators of Pressure and pH.

PurposeThe concentration of protons in the aqueous humor (AH) of the vertebrate eye is maintained close to blood pH; however, pathologic conditions and surgery may shift it by orders of magnitude. We investigated whether and how changes in extra- and intracellular pH affect the physiology and function of trabecular meshwork (TM) cells that regulate AH outflow.MethodsElectrophysiology, in conjunction with pharmacology, gene knockdown, and optical recording, was used to track the pH dependence of transmembrane currents and mechanotransduction in primary and immortalized human TM cells.ResultsExtracellular acidification depolarized the resting membrane potential by inhibiting an outward K+-mediated current, whereas alkalinization hyperpolarized the cells and augmented the outward conductance. Intracellular acidification with sodium bicarbonate hyperpolarized TM cells, whereas removal of intracellular protons with ammonium chloride depolarized the membrane potential. The effects of extra- and intracellular acid and alkaline loading were abolished by quinine, a pan-selective inhibitor of two-pore domain potassium (K2P) channels, and suppressed by shRNA-mediated downregulation of the mechanosensitive K2P channel TREK-1. Extracellular acidosis suppressed, whereas alkalosis facilitated, the amplitude of the pressure-evoked TREK-1–mediated outward current.ConclusionsThese results demonstrate that TM mechanotransduction mediated by TREK-1 channels is profoundly sensitive to extra- and intracellular pH shifts. Intracellular acidification might modulate aqueous outflow and IOP by stimulating TREK-1 channels.

Potassium-sparing effects of furosemide in mice on high-potassium diets.

In individuals on a regular "Western" diet, furosemide induces a kaliuresis and reduction in plasma K concentration by inhibiting Na reabsorption in the thick ascending limb of Henle's loop, enhancing delivery of Na to the aldosterone-sensitive distal nephron. In the aldosterone-sensitive distal nephron, the increased Na delivery stimulates K wasting due to an exaggerated exchange of epithelial Na channel-mediated Na reabsorption of secreted K. The effects of furosemide are different in mice fed a high-K, alkaline (HK) diet: the large-conductance Ca-activated K (BK) channel, in conjunction with the BK β4-subunit (BK-α/β4), mediates K secretion from intercalated cells (IC) of the connecting tubule and collecting ducts. The urinary alkaline load is necessary for BK-α/β4-mediated K secretion in HK diet-fed mice. However, furosemide acidifies the urine by increasing vacuolar ATPase expression and acid secretion from IC, thereby inhibiting BK-α/β4-mediated K secretion and sparing K. In mice fed a low-Na, high-K (LNaHK) diet, furosemide causes a greater increase in plasma K concentration and reduction in K excretion than in HK diet-fed mice. Micropuncture of the early distal tubule of mice fed a LNaHK diet, but not a regular or a HK diet, reveals K secretion in the thick ascending limb of Henle's loop. The sites of action of K secretion in individuals consuming a high-K diet should be taken into account when diuretic agents known to waste K with low or moderate K intakes are prescribed.

КИСЛОТНО-ОСНОВНАЯ БУФЕРНОСТЬ ПОЧВ В СВЯЗИ С ИХ АГРОГЕННОЙ АЦИДИЗАЦИЕЙ ПРИ ВОЗДЕЛЫВАНИИ ЧАЯ В СУБТРОПИКАХ РОССИИ

Based on long experience with fertilizers on tea culture in the conditions of the Sochi Black Sea coast, the buffer properties of brown forest acid soils, acidified in various degrees as a result of the use of single (111), double (222) and triple (333) doses of NPK were studied. The total load of nitrogen fertilizers (the main factor of acidification) for 26 years of use was 3.8-7.6-11.4 tons N/ha. Comparison was made with the soil without fertilizers (000) and forest soil. The identical capacity of soil buffering relative to the hydroxyl load was revealed: shift by 1 and 2 pH units with the introduction of 2.5 and 10.0 mEq NaOH per 100 g of soil. Soil resistance to acid loads was increasing in the series: forest — 000 — 111 — 222 — 333. The highest buffer capacity under increasing proton load was found in soils with a high degree of acidification as a result of the use of double and triple doses of NPK. For them, a shift of 2 pH units was achieved by adding into the suspension about 12.5 mEq HCl per 100 g of soil, while for others it was about 7.5 mEq HCl per 100 g of soil. The resistance of some soils (222 and 333) to acid loads was higher than to alkaline loads, while the resistance of others (forest, 000, 111) on the contrary.

Low - cost multilayered green fiber for the treatment of textile industry waste water.

Layer by layer (LbL) assembly can be regarded as an emerging technology for the separation of organic micro-pollutants from water. Direct assembly of polyelectrolytes (PEs) under LbL mode on natural support material is rare. Here we report the integration of LbL to one of the most resourceful support materials that might have an enduring impact on water treatment in color industry. A low-cost adsorbent is developed from chitosan (CHI) and polyacrylic acid (PAA) through LbL deposition on coir fiber (CF) by alternate exposure to their aqueous solutions. Their layer dependent formation is characterized by spectroscopic and microscopic techniques. CHI/PAA multilayer coated coir fiber or simply, layered coir fiber (LCF) showed high loading of cationic and anionic dyes both at acidic and alkaline loading pH. The loading was between 70% and 99% at the acidic pH 3 which is attributed to the binding between LCF and dye molecules by electrostatic and hydrophobic forces. The performance of LCF in presence of NaCl, Na2SO4 and sodium dodecyl sulfate (SDS) in dye solution is discussed. Textile industrial waste water showed significant reduction in dye (81%) content along with COD (84%) and TDS.

RNA SEQ Analysis Indicates that the AE3 Cl\u2212/HCO3\u2212 Exchanger Contributes to Active Transport-Mediated CO2 Disposal in Heart

Loss of the AE3 Cl−/HCO3− exchanger (Slc4a3) in mice causes an impaired cardiac force-frequency response and heart failure under some conditions but the mechanisms are not known. To better understand the functions of AE3, we performed RNA Seq analysis of AE3-null and wild-type mouse hearts and evaluated the data with respect to three hypotheses (CO2 disposal, facilitation of Na+-loading, and recovery from an alkaline load) that have been proposed for its physiological functions. Gene Ontology and PubMatrix analyses of differentially expressed genes revealed a hypoxia response and changes in vasodilation and angiogenesis genes that strongly support the CO2 disposal hypothesis. Differential expression of energy metabolism genes, which indicated increased glucose utilization and decreased fatty acid utilization, were consistent with adaptive responses to perturbations of O2/CO2 balance in AE3-null myocytes. Given that the myocardium is an obligate aerobic tissue and consumes large amounts of O2, the data suggest that loss of AE3, which has the potential to extrude CO2 in the form of HCO3−, impairs O2/CO2 balance in cardiac myocytes. These results support a model in which the AE3 Cl−/HCO3− exchanger, coupled with parallel Cl− and H+-extrusion mechanisms and extracellular carbonic anhydrase, is responsible for active transport-mediated disposal of CO2.

Role of Cl- -HCO3- exchanger AE3 in intracellular pH homeostasis in cultured murine hippocampal neurons, and in crosstalk to adjacent astrocytes.

A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive. Comparisons of cells from wild-type vs. AE3-/- mice show that AE3 (present in hippocampal neurons, not astrocytes; mediates HCO3- efflux) enhances intracellular pH (pHi ) recovery (decrease) from alkali loads in neurons and, surprisingly, adjacent astrocytes. During metabolic acidosis (MAc), AE3 speeds initial acidification, but limits the extent of pHi decrease in neurons and astrocytes. AE3 speeds re-alkalization after removal of MAc in neurons and astrocytes, and speeds neuronal pHi recovery from an ammonium prepulse-induced acid load. We propose that neuronal AE3 indirectly increases acid extrusion in (a) neurons via Cl- loading, and (b) astrocytes by somehow enhancing NBCe1 (major acid extruder). The latter would enhance depolarization-induced alkalinization of astrocytes, and extracellular acidification, and thereby reduce susceptibility to epileptic seizures. The anion exchanger AE3, expressed in hippocampal (HC) neurons but not astrocytes, contributes to intracellular pH (pHi ) regulation by facilitating the exchange of extracellular Cl- for intracellular HCO3- . The human AE3 polymorphism A867D is associated with idiopathic generalized epilepsy. Moreover, AE3 knockout (AE3-/- ) mice are more susceptible to epileptic seizure. The mechanism of these effects has been unclear because the starting pHi in AE3-/- and wild-type neurons is indistinguishable. The purpose of the present study was to use AE3-/- mice to investigate the role of AE3 in pHi homeostasis in HC neurons, co-cultured with astrocytes. We find that the presence of AE3 increases the acidification rate constant during pHi recovery from intracellular alkaline loads imposed by reducing [CO2 ]. The presence of AE3 also speeds intracellular acidification during the early phase of metabolic acidosis (MAc), not just in neurons but, surprisingly, in adjacent astrocytes. Additionally, AE3 contributes to braking the decrease in pHi later during MAc in both neurons and astrocytes. Paradoxically, AE3 enhances intracellular re-alkalization after MAc removal in neurons and astrocytes, and pHi recovery from an ammonium prepulse-induced acid load in neurons. The effects of AE3 knockout on astrocytic pHi homeostasis in MAc-related assays require the presence of neurons, and are consistent with the hypothesis that the AE3 knockout reduces functional expression of astrocytic NBCe1. These findings suggest a new type of neuron-astrocyte communication, based on the expression of AE3 in neurons, which could explain how AE3 reduces seizure susceptibility.

Modelling of pretreatment and saccharification with different feedstocks and kinetic modeling of sorghum saccharification

Experiments have been performed for pretreatment of sorghum, wheat straw and bamboo through high temperature alkali pretreatment with different alkaline loading and temperatures, and the data on extent of delignification in terms of the final compositions of cellulose, hemicellulose and lignin have been generated. Further, enzymatic saccharification has been carried out in all the cases to find the extent of conversion possible after 72h. The effect of different operating parameters on the extent of delignification and cellulose conversion are evaluated. This data is employed to develop a generalized multi-feedstock and individual feedstock based models which can be used to determine the extent of delignification and cellulose conversion for any and specific biomass respectively with alkaline pretreatment and similar enzyme conditions as considered in the present study. Also, a kinetic model is developed and validated for sorghum for cellulosic conversion.

Effect of Anthraquinone on Alkaline Pretreatment and Enzymatic Kinetics of Sugarcane Bagasse Saccharification: Laboratory and Pilot Scale Approach

A laboratory (2 L) scale alkaline pretreatment with and without anthraquinone addition was performed to evaluate the influence of temperature, alkaline loading, residence time, heating and stirring system on mass yield and solubilization rates of the main components. The best conditions were scaled up to pilot scale (350 L), and enzymatic conversion of structural carbohydrates into sugars for cellulosic ethanol production was analyzed. The tested conditions were 130–170 °C, 0.5–1.5% NaOH, 30–90 min with and without 0.15% w/w of anthraquinone (AQ). The AQ addition did not lead to substantial cellulose preservation in the laboratory scale; however, in the pilot scale the AQ addition resulted in 67.4% and 28.5% of cellulose preservation for reactions at 130 °C, 1.5% NaOH, 30 min (5Pil) and 170 °C 1.5% NaOH, 30 min (7Pil) respectively in relation to those studies without addition. The most efficient heating and agitation system of pilot reactor was probably the determining factor for effective performance. Te...

Maintaining K+ balance on the low-Na+, high-K+ diet.

A low-Na+, high-K+ diet (LNaHK) is considered a healthier alternative to the "Western" high-Na+ diet. Because the mechanism for K+ secretion involves Na+ reabsorptive exchange for secreted K+ in the distal nephron, it is not understood how K+ is eliminated with such low Na+ intake. Animals on a LNaHK diet produce an alkaline load, high urinary flows, and markedly elevated plasma ANG II and aldosterone levels to maintain their K+ balance. Recent studies have revealed a potential mechanism involving the actions of alkalosis, urinary flow, elevated ANG II, and aldosterone on two types of K+ channels, renal outer medullary K+ and large-conductance K+ channels, located in principal and intercalated cells. Here, we review these recent advances.

A physicochemical method for increasing methane production from rice straw: Extrusion combined with alkali pretreatment

Pretreatment is a crucial processing step in the conversion of lignocellulosic biomass (LB) into methane by anaerobic digestion. A physicochemical LB pretreatment method, i.e., using an extruder to reduce the biomass size prior to sodium hydroxide (NaOH) pretreatment, was reported. The optimal condition for economic feasibility and pretreatment efficiency was an alkaline loading rate of 3.0% at 35°C for 48h. Under this condition, the methane production from the rice straw that was processed by extrusion combined with NaOH pretreatment was 54.0% higher than that of a control sample. The energy recovery (ER) efficiency improved from 38.9% to 59.9% using the combination pretreatment. The mechanisms that caused the significant improvement in the methane production and ER efficiency in the extrusion–NaOH pretreatment were investigated. The pretreatment changed the physical properties (water-holding capacity, specific porosity, specific surface area and crystallinity index), the chemical composition (lignin, benzene–ethanol extractives and hot-water extractives) and the chemical structure, which increased degradation of holocelluloses and other difficulty biodegradable compounds.

Chalcone isothiocyanate-mesoporous silicates: Selective anchoring and toxic metal ions detection

Nanosensors are one of the important applications of mesoporous materials used for toxic metal ions detection. Here, a rational strategy aimed at designing 2D and 3D nanosensors using SBA-15 and KIT-6 types of mesoporous silicates as probe carriers. A novel ligand of chalcone analogue namely, chalcone isothiocyanate, CITC has been synthesized. Covalent anchoring of CITC into mesoporous silicates was performed through two methods: (i) loading via the coupling agent (3-aminopropyl) trimethoxysilane (APS) into calcinated mesoporous silicates, (ii) alkaline loading into amino-functionalized mesoporous silicates. The obtained mesoporous silicates and their CITC anchored forms were characterized using different spectroscopic techniques. The results indicated the higher efficiency of KIT-6 and APS loading method than both SBA-15 and alkaline loading method. Therefore, a highly sensitive nanosensor used for toxic metal ions detection was successfully designed by the anchoring of CITC into KIT-6 via the more efficient APS method. Among of metal ions, the most widely toxins, Cd(II), Co(II) and Sb(III) were studied. The optical sensing of these metal ions was performed using electronic absorption and emission techniques. The absorption spectra increase gradually upon increasing the concentrations of the used metal ions, with significant color changes. Also, a great enhancement in the fluorescence intensity was observed upon adding these metal ions. The spectral changes can be rationalized in terms of the formation of [M(CITCs-KIT-6)n]2+ complexes. These results suggested that CITC/KIT-6 nanosensor is suitable for the on-line analysis and in situ detection of these toxic ions in potable and environmental water samples.

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