Concentrations Of Soluble Ions Research Articles

New estimates of sulfate diffusion rates in the EPICA Dome C ice core

Abstract. To extract climatically relevant chemical signals from the deepest, oldest Antarctic ice, we must first investigate the degree to which chemical ions diffuse within solid ice. Volcanic sulfate peaks are an ideal target for such an investigation because they are high-amplitude, short-duration (∼3 years) events with a quasi-uniform structure. Here we present an analysis of the EPICA Dome C sulfate record over the last 450 kyr. We identify volcanic peaks and isolate them from the non-sea-salt sulfate background to reveal the effects of diffusion: amplitude damping and broadening of peaks in the time domain with increasing depth and age. Sulfate peak shape is also altered by the thinning of ice layers with depth that results from ice flow. Both processes must be simulated to derive effective diffusion rates. This is achieved by running a forward model to diffuse idealised sulfate peaks at different rates while also accounting for ice thinning. Our simulations suggest a median effective diffusion rate of sulfate ions of 2.4±1.7×10-7 m2 yr−1 in Holocene ice, slightly faster than suggested by previous work. The effective diffusion rate observed in deeper ice is significantly lower, and Holocene ice shows the highest rate of the last 450 kyr. Beyond the Holocene, there is no systematic difference between the effective diffusion rates of glacial and interglacial periods despite variations in soluble ion concentrations, dust loading, and ice grain radii. Effective diffusion rates for 40 to 200 ka are relatively constant and of the order 1×10-8 m2 yr−1. Our results suggest that the diffusion of sulfate ions within volcanic peaks is relatively fast initially, perhaps through an interconnected vein network, but slows significantly after 40 kyr. In the absence of clear evidence for a controlling influence of temperature on sulfate diffusivity with depth and age, we hypothesise that the rapid decrease in effective diffusion rate from the time of deposition to ice of 50 ka age may be due to a switch in the mechanism of diffusion resulting from the changing location of sulfate ions within the ice microstructure and/or interconnectedness of veins and grain boundaries.

Assessment of marine and urban-industrial environmental impact on stone acting as the base of a quaternary bronze sculpture

This work investigates the influence of a marine and urban-industrial environment on the deterioration of a funerary memorial in Getxo (Basque Country, Spain). The sculpture and artificial stone materials as well as their degradation products were characterised via a multi-analytical approach. An in situ characterisation of the bronze statue and its artificial limestone base was carried out with portable Energy Dispersive X-Ray Fluorescence (ED-XRF) and Raman spectrometers. In addition, several samples of white crusts as well as metal runoff crusts and biological patina were collected and some of them were prepared as cross-sections. High Resolution Micro-X-ray fluorescence and micro-Raman spectroscopy were used as non-destructive methods to detect original and degradation compounds. The test of soluble salts was also carried out on the samples and ion chromatography was employed in the laboratory. Exclusively calcite salt-efflorescences were found at the monument side with ED-XRF and Raman spectroscopy. While their morphology was compact at unsheltered sites, they showed a lamellar structure at sheltered locations, whose increased volume strongly influences the destruction of the memorial. The spectroscopic characterization of metal runoff showed that its excessive occurrence on the memorial surface was due to the dissolution of the copper-alloy caused by chemical reactivity with the surrounding acidic atmosphere. The formation of brochantite Cu4(SO4)(OH)6, posnjakite Cu4(SO4)(OH)6·(H2O), langite Cu4(SO4)(OH)6·2(H2O), or malachite Cu2(CO3)(OH)2 was favored exclusively in metal runoff crusts at unsheltered locations. However, much thinner crusts collected at sheltered sites showed a different composition, with copper species such as moolooite (Cu(C2O4)·nH2O) and atacamite Cu2Cl(OH)3. The soluble salt extraction showed a variable concentration of soluble ions depending on the area where the samples come from. The sample from north west sheltered location showed the highest content of sulfate, nitrate and chloride compounds. In addition, the concentration of fluoride and nitrate reflects the impact of contamination of surrounding industries.

Understanding the role of magnetic (Fe3O4) nanoparticle to mitigate cadmium stress in radish (Raphanus sativus L.)

Heavy metals stress particularly cadmium contamination is hotspot among researchers and considered highly destructive for both plants and human health. Iron is examined as most crucial element for plant development, but it is available in inadequate amount because they are present in insoluble Fe3+ form in soil. Fe3O4 have been recently found as growth promoting factor in plants. To understand, a sand pot experiment was conducted in completely randomized design (control, cadmium, 20 mg/L Fe3O4 nanoparticles,40 mg/L Fe3O4 nanoparticles, 20 mg/L Fe3O4 nanoparticles + cadmium, 40 mg/L Fe3O4 nanoparticles + cadmium) to study the mitigating role of Fe3O4 nanoparticles on cadmium stress in three Raphanus sativus cultivars namely i.e., MOL SANO, MOL HOL PARI, MOL DAQ WAL. The plant growth, physiological and biochemical parameters i.e.,shoot length, shoot fresh weight, shoot dry weight, root length, root fresh and dry weight, MDA content, soluble protein contents, APX, CAT, POD activities and ion concentrations, membrane permeability, chlorophyll a, chlorophyll b and anthocyanin content, respectively were studied. The results displayed that cadmium stress remarkably reduces all growth, physiological and biochemical parameters for allcultivars under investigation. However, Fe3O4 nanoparticles mitigated the adverse effect of cadmium by improving growth, biochemical and physiological attributes in all radish cultivars. While, 20 mg/L Fe3O4 nanoparticles have been proved to be more useful against cadmium stress. The outcome of present investigation displayed that Fe3O4 nanoparticles can be utilized for mitigating heavy metal stress.

Dissolution behavior and aging of iron–uranium oxide

Understanding the dissolution behavior of the fuel debris is necessary for the safe decommissioning of Fukushima Daiichi Nuclear Power Plants. The dissolution behavior of FeUO4 compounds formed by a high-temperature reaction of UO2 with iron, a stainless-steel component of reactor structural materials, was investigated under atmospheric conditions. The compounds were prepared in an electric furnace using U3O8 and Fe3O4 as starting materials, and their solid states were analyzed using X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray absorption fine-structure spectroscopy. The fission products were produced via thermal-neutron irradiation. The concentration of nuclides dissolved in water was examined by performing static leaching tests of FeUO4 compounds for up to three months. A redox reaction was proposed to occur between trivalent Fe and pentavalent U ions in the early stage of FeUO4 dissolution. It was thermodynamically deduced that the reduced divalent Fe ion was finally oxidized into a trivalent ion in the presence of dissolved oxygen, and iron hydroxide limited the solubility of Fe. Meanwhile, the concentration of hexavalent U (i.e., uranyl ion) was limited owing to the presence of secondary minerals such as metaschoepite and sodium uranate and subsequently decreased, possibly owing to sorption on Fe oxides, for example. The concentrations of multivalent ions of fission products, such as Ru and Ce, also decreased, likely for the reason above. By contrast, the concentration of soluble Cs ions did not decrease. The validity of this interpretation was supported by comparing the results with the dissolution behavior of a reference sample (Fe-free U3O8).

Formation and migration of soluble ions in condensable particulate matter in limestone-gypsum wet flue gas desulfurization system

In this work, the emission characteristics of condensable particulate matter (CPM) and soluble ions in the inorganic components after wet flue gas desulfurization (WFGD) were investigated by adjusting the operating parameters of the limestone-gypsum WFGD system. Using a combination of US Method 202 and US EPA Method 5 as the primary measurement method, the study is an experimental study and analysis of the properties of CPM emitted from a limestone-gypsum WFGD system. Based on the measurement results, the influence of some important WFGD operating parameters on CPM emissions was evaluated. The results showed that CPM accounts for 84% of total particulate matter (TPM) emissions in desulfurized flue gas. The composition of CPM is primarily inorganic, comprising 96% of the components, with only a small portion being organic at 4%. The CPM that condensed to a solid state was generally less than 1 μm in diameter and mostly came from WFGD process. The analysis of soluble ions showed that Ca2+ and SO42- were the main ionic components in CPM. By adjusting the desulfurization operating parameters (inlet flue gas temperature, desulfurization solution temperature, desulfurization solution concentration), the concentration of soluble ions can be reduced to different degrees, so as to achieve the purpose of reducing CPM emission. This demonstrated that the CPM emission problem of limestone-gypsum WFGD system could be relieved by operating parameter optimization.

Interannual variation and chemical characterization of major water-soluble inorganic ions in snow across Northwest China

From November 2018 to April 2020, 438 snow samples were collected near two field observation sites in Heihe and Altay, Northwest China, and the pH and major water-soluble inorganic ions (Ca2+, SO42−, Na+, NO3−, Cl−, K+, Mg2+, and NH4+) were analyzed. To identify the source of ions, the enrichment factor method, Pearson correlation analysis, and HYSPLIT (Hybrid Single Practical Lagrangian Integrated Trajectory) backward trajectory analysis were employed. The snow was nearly pH neutral, and Ca2+ was the dominant cation present. The anion concentration demonstrated high variability. Affected by geographical location and atmospheric circulation, the concentration of soluble inorganic ions in snow from the Altay region was higher than that in the Heihe region and remote areas at high altitude or high latitude. Compared with 2018/2019, ion concentrations in snow increased in 2019/2020, especially in the Altay region. Moreover, the temporal trend of ion concentrations was stable, indicating that the source and migration path of ions had strong consistency. Our study suggested that terrestrial sources are the main driving factors for the ions observed in snow samples from Northwest China, and some ions are also the result of anthropogenic sources (NH4+, SO42−, and NO3−), marine sources (Cl− and Na+), and salt mine dust (Cl−, Na+, SO42−, and K+).

Salinity Tolerance and Ion Accumulation of Coastal and Inland Accessions of Clonal Climbing Plant Species Calystegia sepium in Comparison with a Coastal-Specific Clonal Species Calystegia soldanella

Plant species adapted to saline habitats represent an important resource in the assessment of salinity tolerance mechanisms. The aim of the present study was to analyze salinity tolerance and ion accumulation characteristics for various accessions of Calystegia sepium from different habitats in comparison to these of Calystegia soldanella in controlled conditions. Plants were introduced in culture using stem explants with leaf and were cultivated in controlled conditions under six different substrate salinities. Salinity tolerance of both C. sepium and C. soldanella plants was relatively high, but the tolerance of particular accessions did not depend on the substrate salinity level in their natural habitats. C. sepium accession from a mesophytic non-saline habitat was only slightly negatively affected by increasing substrate salinity. However, coastal accession of C. sepium and coastal-specific species C. soldanella had some similarities in ion accumulation characteristics, both accumulating a high concentration of soluble ions in aboveground parts and excluding them from underground parts. All C. sepium accessions from different habitats represented varied physiotypes, possibly associated with their genetic differences. C. sepium accessions from different habitats can be suggested as models for further studies aiming at dissecting possible genetic, epigenetic and physiological mechanisms of adaptation to heterogeneous environmental conditions.

Chemistry and buffering capacity of fog water collected in and around New Delhi, India.

In this study, fog water samples collected from New Delhi and its satellite township Sonipat for 2years 2015-16 and 2016-17 are characterized by soluble ions and internal buffering capacity. The pH of fog water is close to 5.6 due to the limited contributions of Ca2+ and Mg2+ ions by virtue of low wind speed during winters. NH4+ and Ca2+ were dominant cations in fog at both sites during both sampling years. NH4+ and Ca2+ contributions were similar in New Delhi during 2015-16, but Ca2+ increased during 2016-17 on account of construction activities. Emissions from agriculture fields through fertilizer applications and animal breeding lead to an increase of NH4+ compared to Ca2+ at Sonipat. SO42- was comparable with Cl-, followed by NO3- ions. Plastic burning in this region during wintertime was a possible source of Cl- ions. Acid neutralization decreases as NH4+ > Ca2+ and Mg2+ for all samples in Sonipat and as Ca2+ > NH4+ and Mg2+ in New Delhi. Higher NO3- in New Delhi was due to vehicular emissions. Vehicular emissions in New Delhi and agriculture fields in Sonipat were dominant sources of organic acids. Observed internal buffering capacity was different than theoretical values over a pH range from 4 to 7 in New Delhi, whereas both buffering capacities were close to each other in Sonipat samples. Lead in fog water at both sites was higher than prescribed safe limits for drinking water. Pollution sources were responsible for higher concentrations of metals, organic acids, and soluble ions in fog in New Delhi compared to that in Sonipat.

Influence of sewage sludge and saline water irrigation on soil soluble ions and nutrient uptake under Pearl millet-Wheat cropping system in semi-arid region

Salinity is the most common problem in arid and semi-arid regions hindering nutrient accumulation in plants. A field trial (2017-18) was carried out to study the effect of sewage sludge (SS) and saline water irrigation on nutrient uptake under the pearl millet-wheat system and soluble ions in the soil. The experiment consisted of three irrigation levels (canal water, 8 and 10 dS/m ECiw saline water) and five fertilizer treatments i.e., control, sewage sludge (SS)- 5 t/ha, SS (5 t/ha) + 50% recommended dose of fertilizer (RDF), SS (5 t/ha) + 75% RDF and 100% RDF where sewage sludge was applied in rabi season only. The results indicated that the saline water irrigation significantly increased the concentrations of soluble ions (Na+, K+, Ca2++Mg2+, HCO3-, SO42- and Cl-) in the soil, and also the increase was non-significant under sewage sludge application. Na+ and Cl- ions were dominated under saline conditions among the soluble ions in the soil. The nutrient (N, P and K) uptake by grain and stover/straw of pearl millet and wheat crops were significantly reduced under saline environment. However, the maximum uptake in both crops was obtained under canal water irrigation (0.35 dS/m). Among fertilizer treatments, the maximum uptake (NPK) in both crops was attained under RDF being at par with SS (5 t/ha) + 75 RDF except K uptake in pearl millet crop, where the highest K uptake was obtained with SS (5 t/ha) + 75 RDF which was remained statistically at par with RDF treatment. The interactive effect was however non-significant. It is concluded that incorporating SS would enhance nutrient uptake in crops under saline conditions besides solving its dumping problem.

Downward migration of salts in termite-affected soils: Implications for groundwater salinization

The Buffels River catchment, in the Northern Cape Province of South Africa, is affected by saline groundwater. Large, shallow, circular earth mounds (around 2 m high and 30 – 40 m diameter) that are associated with termite activity are dominant microtopographical features within the catchment. These mounds (known as heuweltjies) have salinity levels an order of a magnitude higher than the surrounding soils but it was unclear whether the salinity was caused by the upward movement of saline groundwater, or if the downward movement of heuweltjie salts contributed to groundwater salinization. Thus, this study aimed to determine i) the net direction of solute migration through the mound profiles, ii) the association of salts with mound features and iii) possible sources of salinity. Detailed analyses were conducted on two excavated heuweltjies to determine the chemical, mineralogical and physical characteristics of the mounds as well as their salt type and concentration profile. Heatmaps and correlation matrices were generated to show the spatial and statistical relationships between the individual ion species within the heuweltjies. Results showed that heuweltjies have elevated soluble ion concentrations compared to the interheuweltjie soils. Ion activity ratios in the heuweltjies are consistent with a marine-aerosol origin of the soluble ions. High concentrations of salts are associated with termite frass and nest chambers, suggesting termite activity plays a role in their concentration in the mounds. Gypsum and calcite are only present in the heuweltjie soils. Halite is undersaturated throughout both heuweltjies but is least undersaturated in the centres of the heuweltjies. Calcite nears saturation towards the surface of the mounds whereas gypsum reaches saturation at the middle to base of the heuweltjies. This downward separation of increasingly soluble minerals suggests a surface source of salinity that is being transported downward through the heuweltjie. Faunal burrows on the surface of the mound crests form local microtopographic lows, and preferential flow pathways through granular soils and termite nests and tunnels were observed. These aid in the transfer of salts to greater depths. Based on these results it is proposed that heuweltjies form an important conduit transferring marine-derived aerosol salts towards the groundwater through the harvesting activities of termites and that the salt concentrations in the heuweltjies are not the result of capillary rise from an elevated water table.

Effect of long-term saline mulched drip irrigation on soil-groundwater environment in arid Northwest China

Water shortage and soil salinization are the two main factors that are limiting the sustainability of agriculture in arid and semi-arid areas. The mulched drip irrigation (MDI) with brackish groundwater is widely used in the arid areas of Northwest China. In this study, field experiments were carried out to study the effect of long-term MDI with brackish groundwater on the soil and groundwater environment. It was found that the groundwater level decreased in the Peacock river watershed steadily from 2008 to 2019, resulted from escalating groundwater exploitation due to the expanding agricultural irrigation area and increasing irrigation water demand. The decline of groundwater level reduced the evaporation of phreatic surface (ETg) and groundwater recharge from MDI (Rg). The ETg and Rg would be very small, where ETg tended to be zero and Rg would decrease to a constant value, while the water table depth was larger than 3 m. In addition, MDI had little effect on the soil moisture content (SMC) during the MDI period while the groundwater level was shallow (less than 1.9 m), and it increased SMC gradually as the cycle of irrigations increased while the groundwater level was deep (greater than 4.2 m). MDI reduced the concentration of soluble salt ions (Na+, K+ and Cl−) and increased the concentration of Ca2+ and SO42− in the soil. The accumulation of Ca2+ and SO42− in bare soil was more serious than that in the mulched land. The SMC, soil ions concentrations, soil salinity and the total dissolved solids of groundwater decreased significantly with the decrease of the groundwater level, and the salinization degree of the soil and groundwater tended to be weak in the field experimental site. However, groundwater level dropped too much caused by increasing agricultural irrigation would be harmful to the sustainable ecological environment.

Different patterns and origins between northwestern and southeastern Tibetan ice core glaciochemical records over the past century

Atmospheric circulation systems differ between the northern and southern Tibetan Plateau (TP) and are characterized by prevailing westerly winds and the Indian monsoon, respectively. This leads to spatial differences between glaciochemical records in the northwestern and southeastern TP. We compared the spatial differences in major soluble ion concentrations (Ca2+, SO42−, NO3−, NH4+, Cl−, Na+, K+, and Mg2+) during the last century in the Aru (northwestern TP) and East Rongbuk (ER; southeastern TP) ice cores. Ca2+ exhibited the largest difference between the ice cores (2371 ppb in the Aru ice core and 65 ppb in the ER ice core), indicating that crustal processes were more dominant in the Aru ice core. NH4+ accounted for 17% of the total ion concentration in the ER ice core but only 3% in the Aru ice core, which may be related to the Indian monsoon traveling over NH3 emission zones in southern Asia. The major soluble ion concentrations exhibited decreasing trends in the Aru ice core but increasing trends in the ER ice core (P < 0.01). Empirical orthogonal function and backward trajectory analyses indicated that the major soluble ions in the Aru ice core originated from crustal sources in central Asia; those in the ER ice core had crustal, anthropogenic, and oceanic sources from southern Asia. The results from the Aru ice core suggest that dust events and enhanced prevailing westerly winds promoted the deposition of dust aerosols from the Taklamakan Desert and arid and semi-arid regions of central Asia. Contrastingly, the results from the ER ice core suggest that the Indian monsoon transported crustal and anthropogenic sources from southern Asia and oceanic sources from the Bay of Bengal and Arabian Sea. This study contributes to the comprehensive understanding of the differences in glaciochemical records and their causes between the northwestern and southeastern TP.

Osmotic regulation mediates embolism vessel refilling via bark water uptake in Salix Matsudana

The aim of this study was to understand the role of bark water uptake in xylem embolism vessel refilling in Salix matsudana. Isolated branch segments of Salix matsudana were soaked in deionized water. Next, the percent loss of conductivity (PLC), the volume, the osmotic potential (Ψs), the concentrations of soluble sugar and ions in xylem sap and the concentration of NSC in the xylem were measured after 2, 4 and 6 h. The PLC decreased, and the volume of xylem sap increased, compared with initial values after soaking for 2, 4, and 6 h. Moreover, the osmotic potential (Ψs) of xylem sap decreased. The concentrations of ions and soluble sugar in the xylem sap increased significantly compared with the initial concentrations after soaking. Based on our findings, water not only entered the xylem vessels through the bark but also repaired the embolism of branches in a certain time. These findings will contribute to the understanding of the physiological and molecular mechanisms between bark water uptake and embolism repair.

Pervasive diffusion of climate signals recorded in ice-vein ionic impurities

Abstract. A theory of vein impurity transport conceived two decades ago predicts that signals in the bulk concentration of soluble ions in ice migrate under a temperature gradient. If valid, it would mean that some palaeoclimatic signals deep in ice cores (signals from vein impurities as opposed to matrix or grain-boundary impurities) suffer displacements that upset their dating and alignment with other proxies. We revisit the vein physical interactions to find that a strong diffusion acts on such signals. It arises because the Gibbs–Thomson effect, which the original theory neglected, perturbs the impurity concentration of the vein water wherever the bulk impurity concentration carries a signal. Thus, any migrating vein signals will not survive into deep ice where their displacement matters, and the palaeoclimatic concern posed by the original theory no longer stands. Simulations with signal peaks introduced in shallow ice at the GRIP and EPICA Dome C ice-core sites, ignoring spatial fluctuations of the ice grain size, confirm that rapid damping and broadening eradicates the peaks by two-thirds way down the ice column. Artificially reducing the solute diffusivity in water (to mimic partially connected veins) by 103 times or more is necessary for signals to penetrate into the lowest several hundred metres with minimal amplitude loss. Simulations incorporating grain-size fluctuations on the decimetre scale show that these can cause the formation of new, non-migrating solute peaks. The deep solute peaks observed in ice cores can only be explained by widespread vein disconnection or a dominance of matrix or grain-boundary impurities at depth (including their recent transfer to veins) or signal formation induced by grain-size fluctuations; in all cases, the deep peaks would not have displaced far. Disentangling the different signal contributions – from veins, the ice matrix, grain boundaries, and grain-size fluctuations – will aid robust reconstruction from ion records.

A high-efficiency self-healing cementitious material based on supramolecular hydrogels impregnated with phosphate and ammonium

High-efficiency self-healing cementitious materials using hydroxyapatites as healing product were described. Supramolecular hydrogels impregnated with phosphate and ammonium ions were designed. Morphology of the supramolecular hydrogel and its capability to release phosphate in solution, the structure of healing products and the self-healing efficiency were characterized with a range of analytical techniques. Cracks in the cementitious materials with width up to 1 mm are closed and completely healed. The healing product in the cracks without ammonium ions was brushite with a sponge-like morphology. Released ammonium ions reacted with calcium hydroxide in the cement matrix, increasing the concentration of soluble calcium ions up to 300 times that in reference pore solution. Ammonium ions facilitated the formation and aggregation of healing products which were converted into hydroxyapatites, improving the maximum healable crack width.

Antilithiatic effect of watermellon (Citrullus lanatus) juice on Calcium Oxalate kidney stones

Background: Nephourolithiasis is a term refers to kidney stones formation, due to aggregation of minerals leading to the development of crystalluria in kidneys or any part of the urinary tract system. Many herbs were used to fragment and crush renal calculi. Habitually, it is noted that people who suffer from kidney problems are advised to eat large quantities of watermellon fruit then, the patient feels healing, without knowing the scientific reason for this improvement. Objectives The current study was designed to investigate the antilithiatic effects of Fresh Watermelon Juice (FWJ) on calcium oxalate kidney stones. Methods Direct exposure technique between FWJ and enucleate stons was used. The pH, and electrical conductivity (EC) of the exposure solution in addition to the chemical and morphological properties of the renal calculi before and after exposure using X-ray diffraction method (XRD) and scanning electron microscope (SEM) were investigated. Results: after 24 hours of submerging renal calculi with FWJ, the calculi appeared dissolved and fragmented with absence of solidity, rigidity and crystallization. The Ph Value and electrical conductivity (EC) of FWJ increased significantly after 24 hours of submerging the calculi increasing total soluble solids and ion concentrations in the solution. X-ray diffraction showed sharp peaks and intensity of of calcium oxalate calculi indicating a significant change in calculus compositionn, shape and crysallization within 48 hours of exposure FWJ.Scanning electron microscope images of treated and untreated renal calculi showed a significant difference in the shape of the crystals that have been transformed from their regular shape as bipyramids with tetragonal crystal point group symmetry to sculpted and un coordinated particles with the absence of a regular geometric shape of crystals with no clear crystallization patterns. Conclusion: Fresh watermellone juice appears to have a strong effect on the shape and composition and integrity of renal calculi which may aid its expulsion from the body.

Utilization of methanol and acetone as mutual solvents to reduce interfacial tension (IFT) in enhanced oil recovery process by carbonated smart water injection

Carbonated smart water is a new combined chemical enhanced oil recovery method, which is effective in water-oil interfacial tension (IFT) reduction. However, the amount of IFT is weak compared to other methods for reducing IFT, such as the use of surfactants. Adding solvents lighter than water to injecting phase is a new strategy for increasing the solubility of CO2 and subsequently reinforcing reactions leading to IFT reduction. On the other hand, mutual solvents can act in the water-oil interface, similar to surfactants, and reduce IFT. In this study, methanol and acetone were used as mutual solvents in different volumetric proportions at a reservoir temperature of 75 °C and CO2 pressures equivalent of 3.447, 6.894 and 10.342 MPa. The diluted seawater samples were used as the simplest type of smart water and the effect of the concentrations of soluble ions in seawater was investigated in this way. The results, in addition to the further reduction of IFT in the presence of these solvents, show that acetone yields a further reduction compared to methanol. Also, the reduction of IFT has a direct relationship with the pressure of applying CO2 and the presence of solvents in water and the opposite with the amount of salinity of seawater. Hence, the minimum IFT was obtained at a constant temperature of 75 °C and at 10.342 MPa, in the presence of CO2 and 15% of acetone with diluted seawater at a concentration of 11,000 ppm as base fluid.

ON-SITE QUALITY EVALUATION OF SUBSURFACE DRAINAGE WATER FOR SUPPLEMENTAL IRRIGATION IN MASHTOUL AL-SOUQ AREA, SHARKIA GOVERNORATE, EGYPT

The objective of this study was to assess the quality of irrigation water, groundwater and drainage water in Mashtoul El-Souq District, Sharkia Governorate, for the supplemental irrigation purposes to compensate for the lacke of fresh irrigation water required for crops grown in the study area. Six sampels from Nabtit and El-Serw irrigation canals, 26-sampels from observation wells (groundwater) and 6-sampels from the outlets of main subsurface drainage collectors (drainage water) were collected during summer (2017) and winter (2017/2018). To achieve this study, three neighboring sites with already installed subsurface drainage system were selected. Three drainage collectors were choosen (one for each site). Five pizometers (observation wells) were constructed at the first collector, 4 pizometers at the second collector and 4 pizometers at the third collector. Water samples were periodically taken from the drainage network at the dumps of drainage pools in exchange rooms. Water samples were subjected to chemical analyses and then calculating some quality parameters to assess their validity for supplemental agricultural irrigation. Cations, anions, pH and EC were determined. Results showed that PH values ranged from7.6 to 8.0 in irrigation water samples, and the average of salinity (EC) and sodicity (SAR) values in irrigation water samples were 0.63 dSm-1 and 2.09, respectively, low saline and alkaline water which is good for irrigation. The pH values of the drainage water ranged from 7.8 to 8.2, and the average values of EC and SAR values in drainage water samples were 2.1 dSm-1 and 4.52, respectively. According to the division of the US Salinity Lab. (1954), it was classified as C2S1 for irrigation water samples, and for drainage water, the classification lies between C3S2 and C4S2. There were seasonal differences in the concentration of soluble ions. Salinity and sodicity of subsurface water varied from 0.78 to 3.12 dSm-1 and 1.75 to 8.42, respectively. A better strategy for dealing with the disposal of subsurface agricultural drainage water is that the drainage water could be intercepted, isolated from the good-quality water, and reused for the irrigation of suitably salt-tolerant crops other than blending.

Mercury (II) Ions Assessment as a Toxic Waste Hazard in Solution Based on Imagery Data for a Part of Environmental Disaster Management

It has been made and calibrated a device to detect dissolved mercury (II) ions as a toxic hazard using Arduino Uno and color sensor TCS3200. The purpose of this design was to realize a device for detecting dissolved mercury (II) ions as heavy metal pollution based on the relation of soluble mercury ion concentration to the liquid from the imagery data. Conjoint natural and technological disasters like the Mercury may pose tremendous risks to regions which are unprepared for such disasters. The results could be an environmental disaster, particularly when these occur in a highly populated area. Controlling the levels of dissolved mercury ions on a regular basis is a part of the environmental disaster management. The device works by converting any light by the photodiode optical sensor when the output is such a magnitude of an electrical current which proportional to the received light color level. The currents that are processed using the Arduino IDE software to extract the RGB values of the dissolved mercury (II) ions image data. Dissolved mercury ions generally do not have the necessary color, therefore, biocatalyst as reagents to generate color in a solution containing the mercury and this study using the Silver Nanoparticles. After reacted with a solution of known concentration of mercury in the value of the solution then carried out on a sample data collection to determine the RGB color values in the solution. In general, the device can be used as a color calibrator applied to the detection of dissolved mercury (II) ions by the obtained image data.

Phosphogypsum stabilization of bauxite residue: Conversion of its alkaline characteristics.

Reduction of the high alkalinity of bauxite residue is a key problem to solve to make it suitable for plant growth and comprehensive utilization. In this study, phosphogypsum, a waste product from the phosphate fertilizer industry, was used to drive the alkaline transformation of the bauxite residue. Under optimal water washing conditions (liquid/solid ratio of 2 mL/g, 30°C, 24 hr), the impact of quantity added, reaction time and reaction mechanism during phosphogypsum application were investigated. Phosphogypsum addition effectively lowered pH levels and reduced the soluble alkalinity by 92.2%. It was found that the concentration of soluble Na and Ca ions in the supernatant increased gradually, whilst the exchangeable Na+ and Ca2+ in solid phase changed 112 mg/kg and 259 mg/kg, respectively. Ca2+ became the dominant element in the solid phase (phosphogypsum addition of 2%, liquid/solid ratio of 2 mL/g, 30°C, 12 hr). X-ray diffraction data indicated that cancrinite and hydrogarnet were the primary alkaline minerals. SEM images suggested that phosphogypsum could promote the formation of stable macro-aggregates, whilst the content of Ca2+ increased from 5.6% to 18.2% and Na reduced from 6.8% to 2.4%. Treatment with phosphogypsum could significantly promote the transformation of alkalinity cations by neutralization, precipitation and replacement reactions. This research provided a feasible method to promote soil formation of bauxite residue by phosphogypsum amendment.