Source Of Magnesium Research Articles

Effects of supplemental source of magnesium and inclusion of buffer on ruminal microbial fermentation in continuous culture

Magnesium oxide (MgO) is the most common supplemental source of Mg for dairy cows and a proven ruminal alkalizer when supplemented above NRC (2001) recommendations. However, overfeeding MgO may increase feeding costs, whereas the effects of alternative sources of Mg on ruminal fermentation are not well known. Moreover, it is still unclear if Mg supplementation influences the effects of bicarbonate-based buffers on ruminal fermentation. We aimed to evaluate the effect of Mg source on ruminal fermentation with diets formulated to a final concentration of 0.25% Mg, and to determine if the effect of sodium sesquicarbonate as a buffer varies with the source of Mg. We used 8 fermentors in a duplicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments, by combining 2 factors: (1) Mg source: using either MgO or an alternative source consisting of a blend of CaMg(OH)4 and CaMg(CO3)2 (BLN) and (2) sodium sesquicarbonate buffer inclusion, at 0 or 0.6% of dry matter intake. Based on preliminary tests of reactivity, we hypothesized that BLN plus buffer would allow for greater ruminal pH, acetate molar proportion, and NDF digestibility than diets with MgO or without buffer. Four 10-d periods were completed, where the last 3 d were used for pH measurements and collection of samples for volatile fatty acids (VFA), ammonia (NH3-N), Mg solubility, N metabolism, and nutrient digestibility. Effects of Mg source (source), sodium sesquicarbonate inclusion (buffer), and their interaction (source × buffer) were tested with the MIXED procedure of SAS (SAS Institute Inc.). We did not find an effect of Mg source on ruminal fermentation variables; however, concentration of soluble Mg in ruminal fluid was greater for MgO compared with BLN. On the other hand, buffer supplementation increased average ruminal pH, acetate molar proportion, and branched-chain VFA molar proportion; tended to increase NDF digestibility; and decreased both area under the curve and time below pH 6.0. An interaction of source × buffer was found for propionate, butyrate, and NH3-N, the first one decreasing and the 2 others increasing only when buffer was supplemented to the BLN diet. Our results indicate that supplementing Mg with either MgO or BLN promotes similar ruminal fermentation in diets with total concentration of 0.25% Mg. Further evaluations are needed to assess Mg availability and animal performance in dairy cows fed BLN.

To the health of the nation through multi-level educational programs for the population in the field of optimal nutrition

Introduction. Healthy nutrition is the most important component of the quality of life, which is understood as an integral indicator of the mental, physical and social functioning of a person. However, the diet of Russians is not enough vegetables and fruits, dairy products, excess sugar, salt, products containing animal fat and trans fats. Violations of the structure of nutrition, nutritional status lead to the development of alimentary-dependent diseases, primarily cardiovascular, and in particular, arterial hypertension.Goal. Study of alimentary risk factors for arterial hypertension.Materials and methods. The data of the survey of VTSIOM and the company Gideon Richter “Food habits of Russians”, September 2020”, conducted by telephone survey in at least 80 regions (1,600 respondents over 18 years old), are analyzed.Results and discussion. The diet of the adult population of Russia is characterized by a high consumption of animal fat (frequent consumption of fatty dairy products-52% of respondents, butter-61%, sausage products-48%), salt (pickles and marinades – 42%), added sugar (confectionery – 47%) with a lack of fruit, fish and seafood. 23% of respondents add salt to ready meals, and 43% use frying when cooking. Arterial hypertension was noted in 52% of respondents, who, compared to normotonics, less often (32-39%) include in their diet foods that are sources of potassium and magnesium (apricots, bananas, dried fruits, nuts, seeds, etc.), and more often-pickles, marinades (47%) and mayonnaise (45%), containing a large amount of salt, as well as add salt to ready meals (24%).Conclusions. In order to prevent arterial hypertension in Russians, it is necessary to increase their intake of potassium and magnesium, limit the content of table salt in the diet, which will be facilitated by the widespread introduction of educational programs on healthy nutrition.

Modeling of the synthesis conditions impact on the structure of calcium magnesium phosphates

Calcium magnesium phosphates are widely used as bioceramics, sorbents, catalysts, cement, etc. Herein, calcium magnesium phosphates were obtained by chemical precipitation from a solution using dolomite as a source of calcium and magnesium, hydroxyethylidene diphosphonic acid as an inhibitor of crystallization. The chemical composition of synthesized samples was characterized with a molar ratio (Ca + Mg)/P of 1.29–1.52 and Mg/(Mg + Ca) of 0.54–0.65. The effect of various parameters (solution temperature, precipitator addition rate, duration of precipitate aging, solution addition sequence, and method of precipitation washing) on the chemical and phase composition, texture, and morphology of calcium magnesium phosphates by X-ray diffraction, Fourier transform infra-red spectroscopy, differential-thermal and thermogravimetric analyses, N2 adsorption-desorption, scanning electron microscopy, and fractional factorial experiments were studied. It was established that (i) the hydroxyethylidene diphosphonic acid addition, (ii) the sequence of adding reaction solutions, and (iii) the method of precipitation washing had the greatest influence on the chemical and phase composition of the obtained samples. The surface area and pore volume of calcium magnesium phosphates were significantly increased by the introduction of hydroxyethylidene diphosphonic acid up to 265 m2/g and 0.568 cm3/g, which makes it possible to obtain materials with a developed mesoporous structure for adsorptions application.

Volcanic events‐related hydrothermal dolomitisation and silicification controlled by intra‐cratonic strike‐slip fault systems: Insights from the northern slope of the Tazhong Uplift, Tarim Basin, China

AbstractOrdovician carbonate rocks on the northern slope of the Tazhong Uplift in the Tarim Basin are modified to varying degrees by hydrothermal fluids related to multiple tectonic‐thermal events, but the nature, origin and circulation mechanisms of such hydrothermal fluids remain debated. In this article, in situ rare‐earth elements and yttrium (REE + Y) concentrations, previously published geochemical datasets and petrographic investigations are integrated to develop a thermo‐tectonic evolution model to improve understanding of silicification and dolomitisation occurring in the interior of the craton basin. δ30Si values, REE + Y ratios and fluid mixing models using modern black smoker fluid and seawater indicate that magma‐sourced hydrothermal fluids, rather than basinal brine heated by magmatism, are responsible for the precipitation of cherts. Petrological and geochemical evidence suggests that deep‐seated, ultramafic‐derived hydrothermal fluids and/or magmatic fluids associated with Permian volcanism may have been involved in the formation of hydrothermal dolomites in the study area. Accompanying formation and reactivation of the strike‐slip faults on the northern slope of the Tazhong Uplift, small volumes of hydrothermal fluids might have been triggered by seismic pumping. The early formed strike‐slip fault systems may also have served as conduits for the subsequent large‐scale transport of deep‐seated, ultramafic‐derived thermal fluids and/or Permian magmatic fluids, along which fluids were transported upwards at high flow rates. Carbonation of ultramafic rocks through interaction with deep‐seated hydrothermal fluids rich in CO2 may have served as a magnesium and silica source for dolomitisation and silicification. Trans‐tensional troughs on NNE‐trending strike‐slip faults with positive flower structure are favourable locations for dolomitisation and silicification.

Estimated average calcium – magnesium content in day meal in a sample of students from Faculty of Medicine of Sarajevo University

Nutrients are chemical substances obtained from food. They have different roles in body. Some are used as energy source, some as structural materials, and regulating agents. Nutrients may reduce the risks of some diseases. There are some recommendations about dietary intake of these nutrients for optimal health. This study aimed to estimate average calcium and magnesium content in day meal in a sample of students from Faculty of Medicine of Sarajevo University. A cross-sectional study was conducted during academic 2015/16 year at Faculty of Medicine of Sarajevo University. The survey covered 44 students. The research instrument was a self-administered questionnaire, by which 3-Day Diet Record was provided. The average intakes of calcium and magnesium were estimated using Nutritional analysis computer program (Nutrics Professional Nutrition Analysis Software). On daily level average intake of calcium was 718.39±311.14 mg in total sample and average intake of magnesium was 292.57±310.10 mg in total sample. Average Ca/Mg ratio was 2.45. In our sample cheese was top source of calcium with Ca/Mg ratio of 32.5, and bread was top source of magnesium with Ca/Mg ratio of 3.1. These results emphasize the importance of monitoring the food nutrition facts in order to achieve adequate nutrients intake.

Tea as a Source of Biologically Active Compounds in the Human Diet.

Due to the different levels of bioactive compounds in tea reported in the literature, the aim of this study was to determine whether commercially available leaf teas could be an important source of phenolics and selected minerals (copper, manganese, iron, zinc, magnesium, calcium, sodium, potassium) and if the differences in the content of these components between various types of tea are significant. It was found that both the amount of these compounds in tea and the antioxidant activity of tea infusions were largely determined by the origin of tea leaves as well as the processing method, which can modify the content of the studied components up to several hundred-fold. The group of green teas was the best source of phenolic compounds (110.73 mg/100 mL) and magnesium (1885 µg/100 mL) and was also characterised by the highest antioxidant activity (59.02%). This type of tea is a great contributor to the daily intake of the studied components. The average consumption of green tea infusions, assumed to be 3–4 cups (1 L) a day, provides the body with health-promoting polyphenol levels significantly exceeding the recommended daily dose. Moreover, drinking one litre of an unfermented tea infusion provides more than three times the recommended daily intake of manganese. Tea infusions can be a fairly adequate, but only a supplementary, source of potassium, zinc, magnesium, and copper in the diet. Moreover, it could be concluded that the antioxidant activity of all the analysed types of tea infusions results not only from the high content of phenolic compounds and manganese but is also related to the presence of magnesium and potassium.

Co-products from the limestone mining as sources of calcium, magnesium and sulphur

This paper aims at assessing the use of co-products from the limestone mining of the Irati Formation as sources of calcium, magnesium and sulphur. Therefore, a study was carried out at a greenhouse by applying different inputs in a Paleudalf. The inputs consisted of co-products from mining, which were referred to as layer 1, layer 2 and limestone. Such inputs were incorporated in pots at the doses of 0, 0.489, 0.978, 1.956 and 3.912 g kg−1, which equal 0, 0.5, 1, 2 and 4 times the limestone dose required to reach soil pH 6.0. After incubation, soil samples were taken to determine the macronutrients. Subsequently, NPK fertiliser was applied and corn sowing was carried out. The application of the co-products provided average increases in the contents of Ca2+, Mg2+ and S-SO42− in the soil by up to 147, 193 and 166 %, respectively. In addition, other benefits, such as increased soil pH and contents of exchangeable potassium and available phosphorus were found. There was also an increase in the dry mass production of the corn shoots and an accumulation of macronutrients with the doses applied. The application of co-products has the potential for being used as an alternative source of secondary macronutrients.

An unusual occurrence of ferroan magnesite in a tonstein from the Minusinsk Basin in Siberia, Russia

Altered volcanic ash layers are common constituents of coal beds throughout the world and are typically preserved as thinly bedded, kaolinite-rich layers called tonsteins. Two tonsteins from the Minusinsk coal basin in southern Siberia, Russia, were selected for bulk chemistry analysis and the lower tonstein was selected for analysis by X-ray diffraction (XRD) and scanning electron microscopy with an energy dispersive detector (SEM/EDS). In addition to minerals commonly found in tonsteins such as kaolinite, K-feldspar, quartz, apatite, zircon, and sulfide minerals, the mineralogical profile of this tonstein includes a unique groundmass component of ferroan magnesite, confirmed by XRD. Ferroan magnesite has never before been reported in tonsteins and has been only briefly mentioned in one paper as a rare mineral found in freshwater sediments associated with coal. The probable parent magma type of the ash was evaluated using TiO2/Al2O3 and Zr/TiO2 vs. Nb/Y classification plots as well as chondrite-normalized REE distribution profiles. The results indicate a probable magmatic source of rhyolitic to slightly andesitic composition. The magnesium source is enigmatic: felsic to intermediate magmas are typically Mg-poor. Furthermore, a Mg-rich environment during initial clay mineral formation would typically result in a smectite or illite clay mineral assemblage instead of the dominant kaolinite present. Several potential external sources of Mg for ferroan magnesite formation were examined, including marine incursion, hydrothermal activity, and influx of non-marine Mg-rich porewaters. Low total sulfur content and absence of illite make marine incursion improbable, and there is no evidence of hydrothermal influence. Total MgO levels fall well within expected limits for a felsic magmatic source, so there is no clear indication of a large influx of Mg into the system post-depositionally. The most likely explanation of this unusual occurrence of ferroan magnesite is that magnesium and iron-bearing minerals in the volcanic ash and underlying rock layers were dissolved and mobilized by HCO3-bearing solutions from organic material in the peat swamp, which in turn allowed ferroan magnesite to precipitate in the subsurface during diagenesis.

Physicochemical characterization of Amaranth starch insulated by mechanical separations

This work focused on the physicochemical properties of isolated Amaranth starch. Inductively coupled plasma (ICP) showed that amaranth is low-lipid calcium and magnesium source for the human diet. Scanning Electron Microscopy showed that isolated granules are in the range of sub and micro size. DSC starch thermogram showed a gelatinization temperature of 67.9 °C and an enthalpy of 10. 6 J/g suggesting the presence of an ordered crystalline structures. High-resolution X-ray diffraction showed the isolated starch contents nanocrystals with an orthorhombic crystalline structure whose pattern was indexed. The pasting profile showed that this kind of starch has an end cold viscosity as a custard, making it useful for infantile formulations. It does not present dynamic viscosity and would not be a problem when swallowed. A very important finding in this work was that the orthorhombic nanocrystals, after solvation during gelatinization, do not contribute to the apparent viscosity development.

Combined Pretreatment by Ultrasound and Struvite Precipitation of Raw Substrates: A Strategy to Overcome C/N Ratio Unbalance in Nitrogen-Rich Anaerobic Co-Digestion Systems

The present study aimed to optimize the struvite chemical precipitation process in nitrogen-rich anaerobic co-digestion systems. Struvite precipitation experiments were carried out using a mixture of cattle slurry liquid fraction and sewage sludge, with and without ultrasound pretreatment. Marine salt or MgCl2 were used as magnesium source in NH4+:Mg2+ stoichiometric proportions of 1:1.5 and 1:3. Under the tested conditions, ammonium nitrogen and orthophosphate were removed from the mixed liquor with a maximum observed efficiency of 43% and 92%, respectively, when the ultrasound treatment was applied prior to struvite precipitation, using MgCl2 as source of magnesium (NH4+:Mg2+ of 1:3). The operating time was 40 min. Different pretreatments were tested prior to the biomethanization experiments, struvite precipitation, ultrasound and a combination of both pretreatments. The application of ultrasound (with an energy input of 218 kJ L−1) and struvite precipitation (NH4+:Mg2+ of 1:3) increased the methane content in the biogas by 82% and reduced hydraulic retention time by 28%, when compared to the anaerobic co-digestion assays without pretreatment. The hydrolytic pretreatment increased the bioavailability of nitrogen by 5%, thus enhancing the removal efficiency of ammonium nitrogen by 20%. Consequently, an increase in the carbon to nitrogen ratio was observed, favoring the methanogenesis process.

Chemical compositions and volatile compounds of Sabah indigenous durian (Durio dulcis Becc.)

The objective of this present work is to determine the chemical compositions and volatile compounds of Sabah indigenous durian (Durio dulcis Becc.). The results obtained showed that durian had 56.1% moisture, 3.5% protein, 2.8% fat, 1.4% ash, 36.26% carbohydrate, 6.6% dietary fiber and 7.0 µg of vitamin A. The mineral analysis results indicated that Durio dulcis is a good source of potassium, magnesium and phosphorus. Protein analysis found a total of sixteen major amino acids present in durian namely aspartame, serine, glutamin acid, glycine, histidine, arginine, threonine, alanine, proline, thyrosine, valine, methionine, lysine, isoleusine, leusine and phenylaline. A total of thirty-three individual fatty acids components were analysed. Among those, palmitic acid was a predominant saturated fatty acid while oleic acid was the most abundant unsaturated fatty acid. The composition of fatty acids showed that total of monounsaturated fatty acids, polyunsaturated fatty acids and saturated fatty acids were 56.7%, 6.7% and 36.6% respectively. A total of thirty-one volatile compounds were identified, among which alcohols, esters, sulphur-containing compounds and ketones were found to be the major constituents.

Economic feasibility of phosphorus recovery through struvite from liquid anaerobic digestate of animal waste.

Although the struvite crystallization process has proven to be an effective process for the recovery of nutrients from wastewater, this process has not been widely used due to the excessive use of chemicals. In this study, the optimal production conditions, yield, and economic feasibility of struvite using the anaerobic digestion of livestock wastewater were investigated. In addition, the economic feasibility of adding zeolite to improve the productivity of struvite and additionally remove nitrogen was evaluated. The result of the experiment on the struvite yield change according to the molar ratios at pH 9.0 showed that the struvite yield ratio was 99.0% of the stoichiometric yield at the Mg2+ :NH4+ :PO43- molar ratios of 1.2:1.0:1.1. As a magnesium source, MgCl2, concentrated seawater in the seawater desalination process, and MgO were compared, and when MgO was used, struvite productivity and economic efficiency were the best. Also, while the addition of zeolite greatly increased the struvite production and zeolite was also sold as a soil conditioner, the struvite sales benefit was estimated to be 103% of the operating cost.

Dietary magnesium intake in relation to body mass index and glycemic indices in middle school students from the HEALTHY Study.

Data on dietary magnesium intake on the risk of type 2 diabetes mellitus (T2DM) among children and adolescents is limited. We examined whether dietary magnesium intake was related to body mass index (BMI) percentile, and glycemic indices at baseline and at end of the HEALTHY Study for both intervention and control schools. The HEALTHY Study was a multi-component, school-based intervention, to prevent T2DM in children and adolescents from 6th to 8th grades. A secondary data analyses of 2181 ethnically diverse students with completed dietary records, BMI percentile, and plasma insulin and glucose concentrations at baseline (6th grade) and end of study (8th grade) were included from the HEALTHY Study. Dietary magnesium intake was self-reported using the Block Kids Food Frequency Questionnaire. A hierarchical multiple regression model was used to determine the relationships between dietary magnesium intake, BMI percentile, and glycemic indices at baseline and end of the HEALTHY Study, adjusting for magnesium intake from supplements, total energy intake, and fitness level. Dietary magnesium intake was related to BMI percentile at baseline and at end of the HEATHY Study (β = -0.05, 95% CI = -0.02 to 0, p = 0.04; β = -0.06, 95% CI = -0.02 to -0.003, p = 0.004); R 2 [regression coefficient effect size] = 0.03; R 2 = 0.06). Dietary magnesium intake was not related to plasma insulin and glucose concentrations at baseline and end of the HEALTHY Study. Dietary magnesium intake was inversely related to BMI percentile among middle school students from the HEALTHY Study. Research is required to evaluate the dose-response relationship between fruit and vegetable consumption (good sources of magnesium) and risk of T2DM in children and adolescents. This relationship also needs to be explored among different BMI categories.

Factors affecting phosphorus recovery as struvite: Effects of alternative magnesium sources

Phosphorus depletion around the globe has made it a critical element for sustainable agriculture resulting in significant research into options to recover and recycle this non-renewable resource. Phosphorus recovery as struvite usually requires the dosing of supplemental commercial magnesium and can account for between 10 and 75% of the cost of struvite production. Therefore, cheaper alternatives to commercial magnesium sources such as seawater and concentrates from RO desalination plants have been sought. Here, we examine the effects of alternative magnesium sources on the phosphorus removal efficiency, particle size, rate constant, morphology and purity of struvite precipitated from synthetic solutions. It was found that the phosphorus removal reduced for struvite precipitation using seawater (14%) compared to the control (29%), but increased for struvite precipitation using bittern (37%). Precipitation using seawater also increased the calcium content from <0.1% for the control and bittern to 6.6% and reduced the average particle size from 88 μm for the control to 50 μm for seawater and to 67 μm for bittern in 1 L jar tests. Batch reactor tests indicate that both magnesium sources produced struvite, though the particle size was smaller for trials using alternative magnesium sources which may limit the efficiency of solid-liquid separation.

Processing of a Nutrient-Rich Cereal Butter an Alternative to Peanut Butter

Cereal butter were made from sunflower, pumpkin, garden cress, corn, rye and peanut butter served as control. Chemical, physical, microbiological, textural and sensory evaluation of cereal based butter poduced from different types of cereal were analzed using a standard method. Pumpkin had highest protein (30.23%), while sunflower, pumpkin and peanut cereals had the highest amounts of fats (51.46, 49.05 and 48.00%, respectively). Also, corn had the highest amounts (72.56%) of carbohydrate. For microbiological evaluation, data show that total mould count ranged between 1.10 to 1.80 log cfu/g for rye and peanut, respectively. Garden cress is a good source of potassium, calcium, iron, and sodium. Also, Pumpkin is a good source of Magnesium, zinc, Phosphor and Selenium. Sunflower had the highest value of Vitamin B1, B2, B6, B9 and E but garden cress had the highest value of B2, K and C vitamins. The fatty acid composition of cereals reported that palmitic acid was the highest value in rye 21.80%. The Palmitoleic acid ranged from 0.22 to 12.50%, the lowest was peanut and highest occurred in sunflower. The highest of oleic acid was peanut 46.80%. Sunflower had highest Linoleic acid (69.0%) and garden cress had highest of linolenic acid 32.18%. Rye had highest value (20.69%) in Arachidic acid and garden cress scored highest in Eicosenoic acid (13.40%). The microbiological quality of cereals butter samples are total aerobic bacterial counts (TAB) ranged between 1.09 log cfu/g (rye butter) to 1.91 log cfu/g (peanut butter). Garden cress was obtained the higher for viscosity value (16100, 15900 and 15700 cp/s) at 25, 40, 60°C than other cereals butter. In texture analysis, garden cress butter had the highest significant amounts of hardness, cohesiveness, gumminess, chewiness and adhesiveness. Sensory evaluation of sunflower butter had the highest significant amounts of overall acceptability, peanut butter then pumpkin butter (96.30, 88.40 and 79.20, respectively) in all samples. Results could be useful in improving cereal butter processing and delivering sunflower butter to consumers who are more concerned as a functional food, high fat content and peanut allergy.

Development of a Self-Sustaining Wastewater Treatment with Phosphorus Recovery for Small Rural Settlements

Global trends such as climate change and the scarcity of sustainable raw materials require adaptive, more flexible and resource-saving wastewater infrastructures for rural areas. Since 2018, in the community Reinighof, an isolated site in the countryside of Rhineland Palatinate (Germany), an autarkic, decentralized wastewater treatment and phosphorus recovery concept has been developed, implemented and tested. While feces are composted, an easy-to-operate system for producing struvite as a mineral fertilizer was developed and installed to recover phosphorus from urine. The nitrogen-containing supernatant of this process stage is treated in a special soil filter and afterwards discharged to a constructed wetland for grey water treatment, followed by an evaporation pond. To recover more than 90% of the phosphorus contained in the urine, the influence of the magnesium source, the dosing strategy, the molar ratio of Mg:P and the reaction and sedimentation time were investigated. The results show that, with a long reaction time of 1.5 h and a molar ratio of Mg:P above 1.3, constraints concerning magnesium source can be overcome and a stable process can be achieved even under varying boundary conditions. Within the special soil filter, the high ammonium nitrogen concentrations of over 3000 mg/L in the supernatant of the struvite reactor were considerably reduced. In the effluent of the following constructed wetland for grey water treatment, the ammonium-nitrogen concentrations were below 1 mg/L. This resource efficient decentralized wastewater treatment is self-sufficient, produces valuable fertilizer and does not need a centralized wastewater system as back up. It has high potential to be transferred to other rural communities.

Phosphate recovery from aqueous solution via struvite crystallization based on electrochemical-decomposition of nature magnesite

Struvite crystallization was considered to be one of the most promising ways for phosphate recovery. However, the cost of struvite recovery process was too high to be economically attractive. In this work, electrochemical-decomposition of nature magnesite was designed to economically supply magnesium and base for synthesizing struvite, and recover phosphate from aqueous solution. The continuous release of magnesium ions from solid magnesite was achieved by electrochemical action, accompanying by the generation of alkaline solution (pH: 9.0–10.8). The results showed that the electrochemical-decomposition strategy was effective to recover phosphate from aqueous solution as struvite. The key factors of phosphate recovery including current, feed rate, the molar ratio of N/P, initial concentration of phosphate and ammonium, influent pH and plate distance. For a 21-day continuous operation, the recovery rate of phosphate was between 86.6% and 93.3%, confirming the stability of the process. The economic evaluation showed that the proposed electrochemical-decomposition process can reduce the cost of phosphate recovery by up to 60% compare with the traditional chemical process, which using MgSO 4 ·7H 2 O and NaOH. The struvite with typical orthorhombic crystals was obtained from the bottom of the glass container where the effluent was collected, indicating that part of the ammonium in the solution was also recovered. It was considered that the proposed process may be beneficial to increase the profitability of magnesite mining companies and wastewater treatment plants through selling-buying magnesite material, and subsequent use as a cheaper magnesium source for struvite precipitation. • A controllable and facile electrochemical-decomposition strategy to synthesize struvite for recovering PO 4 -P was developed. • Sufficient Mg 2+ and base (pH: 9.0-10.8) was created by electrochemically decomposing magnesite for struvite crystallization. • The phosphate can be effectively recovered from aqueous solution as struvite by the electrochemical-decomposition process. • The electrochemical process can reduce the cost by up to 60% compare with traditional chemical process.

Prediction of adequate pH and Mg2+dosage using an empirical MgO solubility model for struvite crystallization

The struvite crystallization process can recover struvite crystals as valuable slow-release fertilizers from raw water, including high phosphate and ammonium ions. MgO can be used as a magnesium source and an alkaline chemical simultaneously; however, it is difficult to control the dissolved Mg 2 + concentration because of its insufficient and unpredictable solubility. The purpose of this study was to estimate MgO solubility and determine the optimal operating conditions of pH and Mg 2 + dosage during struvite crystallization. An empirical MgO solubility prediction model was devised to dose an adequate amount of MgO slurry in accordance with the properties of raw water. MgO solubility was determined by H + ions donated by NH 4 + , HCO 3 − , and H 2 PO 4 - as the pH increased in the solution. It was found that the molar ratio of donated H + to dissolved Mg 2 + converged to 2:1. This model was verified by performing jar-tests using digested sludge filtrate. When adjusting to a pH of 8.0–9.3 using only MgO, the predicted Mg 2 + concentrations using the model were compared to the measured Mg 2 + concentrations, and they coincided well within the maximum error of 5.7%. This model was applied to determining the operating conditions of pH and Mg 2 + dosage. As a result, considering phosphate removal efficiency higher than 90%, it was feasible to simultaneously achieve an Mg/P molar ratio of 1.3–1.5 and a pH of 8.2–8.5 by only using MgO. Therefore, MgO is recommendable as an appropriate magnesium source and alkali supplier in the struvite process based on experimental jar-tests and the empirical MgO solubility model. • An empirical MgO solubility prediction model was devised and applied to struvite crystallization process. • MgO solubility was predicted using pH, and concentrations of acidic ions. • The optimal conditions of pH and Mg 2 + dosage were determined by this model.

Biofortification efficiency with magnesium salts on the increase of bioactive compounds and antioxidant capacity in snap beans

ABSTRACT: Biofortification of food crops is implemented through the application of mineral fertilizers, to improve the levels of essential mineral elements for human nutrition. Magnesium is a key macronutrient in crop production and quality; however, worldwide, it is the most limiting macronutrient in agriculture. Magnesium plays an important role in manipulating physiological and biochemical processes in plants. Therefore, the objective of this study was to evaluate the efficacy of biofortification with magnesium chloride and sulfate on the accumulation of bioactive compounds and antioxidant capacity in snap bean cv. Strike. Two sources of Magnesium were applied via edaphic route: Magnesium chloride and magnesium sulfate at doses of 0, 50, 100 and 200 ppm during 2018 in Mexico. Accumulation of bioactive compounds (total phenols, total flavonoids and total anthocyanins) and antioxidant capacity in snap bean fruits were evaluated. Results obtained indicate that the concentration of total flavonoids, total anthocyanins and antioxidant capacity in the edible parts of snap beans were higher in the MgSO4 treatment than in the MgCl2 treatments, exceeding 30, 59 and 6% respectively. This is one of the first studies on the edaphic agronomic biofortification of Mg+ and its effect on nutraceutical quality in snap bean. An interesting result is that MgSO4 produced high concentrations of anthocyanins in edible snap beans. These results can be applied as a new strategy to reduce malnutrition and improve the health of the population in poor urban and rural communities in developing countries.

Agrotechnical Assessment of Struvite Application

Agrotechnical assessment of struvite produced by a lab-scale sedimentation unit is performed. As a source of phosphates and ammonia, liquor obtained through dewatering of Мunicipal wastewater treatment plant sludge was in use. The range of phosphates and ammonia was in the range of 130 - 250 and 380 - 560 mg/L, respectively. Seawater brine with a magnesium concentration of around 60 g Mg2+/L was applied as a source of magnesium. The agrotechnical characteristics of struvite obtained were compared to ammonium nitrate and carbamide in regards to the productivity effects on maize hybrid P9241. The results show that the effectiveness of struvite and some commercial fertilizers is quite close. The highest yield in the experiment was achieved with the application of carbamide plus ammonium nitrate (56.64 kg/ha), while in applying struvite solely it is 54.60 kg/ha. The highest protein content of maize (9.7%) was observed in the case of struvite/ammonium nitrate application.