High Concentrations Of Ca Research Articles

Study on Salinity Reduction and Changes in Chemical Properties in Saline Soil

Background: The aim of the work was to evaluate the effects of different treatments viz manure as organic amendments, gypsum as amendments and nitrogen resources on salinity of saline soil. Methods: The research was conducted using a 2×4×3 factorial design. The first factor was manure (non-manure and manure), the second factor was the addition of gypsum, @ 0, 0.75, 1.5 and 3.0 ton ha-1) and third factor was source of nitrogen i.e. without N, nitrate and ammonium fertilizer. These three factors were repeated 3 times. Data were analyzed using one-way analysis of variance followed by the Duncan multiple range test for comparisons among means with a significance level of 5%. Result: This research markedly reduced pH, EC, Na and markedly increased sulfate, K content. But CEC, SAR, ESP, total N, nitrate, ammonium were not significant. The highest Ca content was in the 1.5 tons ha-1 gypsum treatment and non manure. Meanwhile, in the interaction between gypsum and N resources, the highest Mg content was 3 tons ha-1 of gypsum and nitrate.

Effect of the microstructure parameters on the mechanical properties and corrosion behavior of Mg alloys with high Zn or Ca content

Effect of the microstructure parameters on the mechanical properties and corrosion behavior of Mg alloys with high Zn or Ca content

Comparison of Pilot-Scale Capacitive Deionization (MCDI) and Low-Pressure Reverse Osmosis (LPRO) for PV-Powered Brackish Water Desalination in Morocco for Irrigation of Argan Trees.

The use of saline water resources in agriculture is becoming a common practice in semi-arid and arid regions such as the Mediterranean. In the SmaCuMed project, the desalination of brackish groundwater (TDS = 2.8 g/L) for the irrigation of Argan trees in Essaouira, Morocco, to 2 g/L and 1 g/L (33% and 66% salt removal, respectively) using low-pressure reverse osmosis (LPRO) (p < 6 bar) and membrane capacitive deionization (MCDI) was tested at pilot scale. MCDI showed 40-70% lower specific energy consumption (SEC) and 10-20% higher water recovery; however, the throughput of LPRO (2.9 m3/h) was up to 1.5 times higher than that of MCDI. In addition, both technologies were successfully powered by PV solar energy with total water costs ranging from EUR 0.82 to EUR 1.34 per m3. In addition, the water quality in terms of sodium adsorption ratio was slightly higher with LPRO resulting in higher concentrations of Ca2+ and Mg2+, due to blending with feed water. In order to evaluate both technologies, additional criteria such as investment and specific water costs, operability and brine disposal have to be considered.

Bioreduction and mineralization of Cr(VI) by Sporosarcina saromensis W5 induced carbonate precipitation.

The microbial reduction of Cr(VI) to Cr(III) is widely applied, but most studies ignored the stability of reduction products. In this study, the Cr(VI)-reducing bacterium of Sporosarcina saromensis combined with microbially induced carbonate precipitation (MICP) was used to explore the reduction and mineralization mechanisms of Cr(VI). The results indicated that the high concentration of Ca2+ could significantly enhance the reduction and mineralization of Cr(VI). The highest reduction and mineralization efficiencies of 99.5% and 55.9% were achieved at 4g/L Ca2+. Moreover, the urease activity of S. saromensis in the experimental group was up to 13.28 U/mg NH3-N. Besides, the characteristic results revealed that Cr(VI) and reduced Cr(III) were absorbed on the surface or got into the interspace of CaCO3, which produced a new stable phase (Ca10Cr6O24(CO3)). Overall, the combination of S. saromensis and MICP technology might be a high-efficiency and environmentally friendly strategy for further application in the Cr(VI)-containing groundwater.

In situ LIBS-XRF analysis as a combined approach to disclose the production technology of unique wall mirrors from Pompeii

It is assumed that the unique wall mirrors found at the Archaeological Park of Pompeii (PAP) are made of obsidian. To contribute to the knowledge of those archaeological artefacts, this work proposes in situ elemental analyses in collaboration with PAP seeking to determine, in a total no-destructive way, the composition and provenance of the main mirror preserved at the House of Gilded Cupids. Comparing the geochemical composition of this black glass with that of obsidian samples collected from the main Mediterranean sources, both X-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS) confirmed an incompatible content of many key elements. LIBS in-depth analysis excluded the potential relation between the higher concentration of Ca and Mg and the presence of alteration products. In addition, XRF analysis missed the detection of Rb, Y, Zr and Nb, which are widely recognized as the elemental fingerprints of obsidian sources. Combined with the detection of a high content of strontium (500–700 ppm), the in situ elemental data proved that, rather than made of obsidian, the analysed mirror was handcrafted by the fusion of coastal sand. Waiting to extend this study to the other mirrors found at Pompeii, the results here presented indicate the history of these unique artefacts needs to be rewritten.

Large-Scale Hydraulic Performance Testing of a Geotextile Mechanically Stabilized Earth (MSE) Wall Constructed with Recycled Concrete Aggregate Backfill

Abstract Constructing geosynthetic mechanically stabilized earth walls with recycled backfill materials reduces environmental impacts and financial cost compared with their gravity wall counterparts. While a large database of column-scale tests to evaluate the hydraulic performance of recycled backfill materials exists in the literature, clogging potential under multidimensional flow conditions has not been examined. A large-scale reinforced soil wall and a complementary column test constructed with recycled concrete aggregate (RCA) and closely-spaced woven geotextile reinforcement were tested to examine chemical and physical clogging under wetting-drying cycles. Internal moisture migration and the evolving chemical signature of leachate were measured. Geotextile samples were exhumed after the tests and analyzed to evaluate chemical (tufa formation) and physical (fines migration) clogging. The complementary multidimensional and column experiments afford direct comparison of outflow chemistry and effects on geotextile permittivity. Geotextiles in the large-scale wall and column tests did not show any evidence of chemical or physical clogging and no evidence of positive pore pressures was detected. Outflow leachate from the wall test had higher total dissolved solids values and higher concentrations of Ca and SO4 in comparison to the column test. The pH of leachate from the column test is initially lower than from the wall, but results become similar (pH ∼12) at test completion. Leachate from both tests is supersaturated with tufa minerals. Differences in leachate characteristics of the two tests can be attributed to the initial moisture content of the backfill, larger quantity of RCA material in the large-scale wall, and the multidimensional flow characteristics of the large-scale wall. Results validate previous observations from column tests in terms of moisture retention and chemical response when flow conditions are multidimensional. Maintaining a free-draining backfill under conditions that could promote clogging (closely-spaced woven geotextile reinforcement layers) gives further confidence in using RCA as backfill under these conditions.

Cultivation of carbohydrate-rich microalgae with great settling properties using cooling tower wastewater

Wastewater treatment and simultaneous production of value-added products with microalgae represent a sustainable alternative. Industrial wastewater, characterized by high C/N molar ratios, can naturally improve the carbohydrate content in microalgae without the need for any external source of carbon while degrading the organic matter, macro-nutrients, and micro-nutrients. This study aimed to understand the treatment, reuse, and valorization mechanisms of real cooling tower wastewater (CWW) from a cement-processing industry mixed with domestic wastewater (DW) to produce microalgal biomass with potential for synthesis of biofuels or other value-added products. For this purpose, three photobioreactors with different hydraulic retention times (HRT) were inoculated simultaneously using the CWW-DW mixture. Macro- and micro-nutrient consumption and accumulation, organic matter removal, algae growth, and carbohydrate content were monitored for 55 days. High COD (> 80%) and macronutrient removals (> 80% of N and P) were achieved in all the photoreactors, with heavy metals below the limits established by local standards. The best results showed maximum algal growth of 1.02 g SSV L−1 and 54% carbohydrate accumulation with a C/N ratio of 31.24 mol mol−1. Additionally, the harvested biomass presented a high Ca and Si content, ranging from 11 to 26% and 2 to 4%, respectively. Remarkably, big flocs were produced during microalgae growth, which enhanced natural settling for easy biomass harvesting. Overall, this process represents a sustainable alternative for CWW treatment and valorization, as well as a green tool for generating carbohydrate-rich biomass with the potential to produce biofuels and fertilizers.

Effects of calcium on phosphorus recovery from wastewater by vivianite crystallization: Interaction and mechanism analysis

Phosphorus recovery by vivianite from different types of wastewater has attracted considerable attention recently. However, the existence of calcium (Ca) would unavoidably affect the formation of vivianite. In this work, the effect of calcium on vivianite crystallization was investigated. The pH of the solutions with low Ca concentration (1–10 mg/L) increased by only 0.06 compared to the conditions without Ca, while a more visible change occurred at high concentrations. Besides, higher removal rate of phosphorus was obtained at higher Ca concentration and the residual amount of Fe in the supernatant increased from 2.01 mg/L in control to 27.29 mg/L at 100 mg Ca/L, indicating competition between Ca and Fe ions. Furthermore, microscopic observation revealed that Ca caused the surface of vivianite to be covered by fine particles, resulting in the inhibition of vivianite growth. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis demonstrated the fine particles covering in the surface of vivianite crystals were mainly amorphous Ca3(PO4)2 and the formation of Fe-phosphate (s) also led to the decrease of the recovery rate and purity of vivianite. The zeta potential of the recovered product indicated that electrostatic adsorption existed in the process and complemented with surface adsorption to become the main routes of Ca binding. The results obtained herein will provide a theoretical basis for understanding the interference of calcium with vivianite crystallization.

Soil Fertility Reclamation of Abandoned Mining Sites through Organic Intervention

Tin mining in the period of its boom left large areas of land unsuitable for crop production. The financial benefits of tin mining were short-lived and cannot be quantified with the consequences of its devastation, which is still negatively impacting on the environment. Many of the devastated lands were abandoned due to soil infertility. Smallholder farmers are battling with restoring soil fertility for crop production. This study was conducted on smallholder farms in a devastated and abandoned area due to tin mining of the Bukuru-Rayfield, Sabon-Gida mining zone of Jos Plateau where contrasting organic interventions by farmers were observed. This was also confirmed by laboratory and geostatic spatial variation. A total of 35 soil samples were taken at a depth of 0-20cm, prepared and analyzed in the laboratory. Continuous surfaces were later generated through geostatistics. Results indicated that organic matter had significant negative correlations with exchangeable acidity (-0.879), clay (-0.633) and silt (-0.616) but significant positive correlations with potential hydrogen (pH) (0.885), nitrogen (N) (0.991), phosphorus (P) (0.954), potassium (K) (0.911), calcium (Ca) (0.920), magnesium (Mg) (0.911) and sand (0.824). Most of these correlations were done at 0.01 level of significance. High concentration of pH, organic matter (OM), N, K, Ca, Mg and sand occurred in the north western part of the study area (Farm A). In contrast, exchangeable acidity, silt and clay had less concentration in the north western part of the study area (Farm A), with highest concentration in the W and SW parts (Farm C). Spatial variability from geostatistics indicated that all the soil variables had strong spatial dependency. The results of this study unveiled that nutrients needed for higher productivity were made available by the smallholder farmer of farm A through dumping of households’ domestic wastes for ten years. These abandoned mining sites later became agriculturally productive. This study will serve as advisory to smallholder farmers as a way of improving soil productivity in tin-devastated farmlands.

Innovative Ingredients Fortified Nutrients Enriched Biscuits and Cookies: Quality and Sensory Analyses

Abstract:Global suffering from COVID-19 has necessitated augmenting the immunity systems of humans through consumption of macro-micro-nutrients and antioxidant-enriched fortified foods. In this article, fortifications of popular bakery products, viz. biscuits, cookies, have been reviewed, encompassing the novel fortifying ingredients and innovative methods employed with an emphasis on the overall enrichment in the final product quality. A few notable features concerning novel fortified biscuit and fortified cookie have been decisively summarized. Wheat flour blended with 40% sesame-cake flour resulted in a fortified biscuit possessing higher protein (16.6%), crude fat (16.95%), and dietary fiber (8.2%) with acceptable sensory characteristics. About 9% toting up of chicken-eggshell dried-powder could result in high Ca content in biscuits with customary changes in texture and sensory properties. A remarkable 5% addition of bee pollen to wheat flour appreciably improved the nutrient compositions (carbohydrate 65.18%, protein 7.32%, and total dietary-fiber 1.47%) along with high polyphenol and antioxidant potentials. Notably, mixing fish fillet protein concentrate with wheat flour could yield enhanced nutritional content (protein 14.63-19.52%, fat 16.2-16.5%), as well as augmented amino acids. Remarkably, wheat flour fortified with fermented jack bean flour resulted in an overall fortified biscuit with substantial carbohydrate, crude protein, fat, fiber, ash, and appreciable macro-micro mineral contents and sensory characteristics. Innovative fortified cookies were made by blending wheat flour or Brewer’s spent grain flour with one or more ingredients, e.g. full fat soya, mushroom, cardamom powder, moringa leaves, coconut, sweet potato flour rendering amplified values of nutrients, superior physical properties, increased mineral and flavonoid contents and organoleptic qualities.

Cathode Nanophosphors

High-current cathodic pulses on an aluminum electrode in solutions containing sufficiently high concentrations of Mg, Ca, Sr, Al, Sc, Y, or La nitrates in a mixture with H3BO3, HF, H3PO4, or H4P2O7 are accompanied by an intense intrinsic luminescence of a number of heavy metals, the ions of which are captured by salt nanofilms and luminescence under the action of hot electrons when are in an environment characteristic of crystal phosphors. The effect of the cathode nanophosphor (CNP) was found in more than 100 systems; photographs are presented for most of the systems. Ga, In, Tl, Ge, Sn, Pb, Mn, Cu, Ag, Cd, Ce, Tb, and Zr ions were activators. The effect of matrix composition on the spectral and kinetic characteristics of the CNP was shown on several examples; a qualitative description of the phenomenon is given, and the prospects for its application to chemical analysis are considered.

Content of Metals in Cow, Sheep and Goat Milk Samples

Milk is an excellent source of many essential nutrients, including Ca, proteins and vitamin D. Nine metals (Ca, Cd, Cu, Fe, Mg, Mn, Zn, Ni and Pb) in raw and pasteurized milk of cow, sheep and goat were determined by atomic absorption spectrometry, flame technique. The levels of Cd, Fe, Mn, Ni and Pb were below the detection limit of the used method. The concentration ranges for Ca, Mg, Zn and Cu, in all milk samples, were as follows: 459.8-992.8, 59.5-206.8, &lt;LOD-22.31 and &lt;LOD-3.20 mg/L, respectively. The order of the metal levels in regards to concentration was Ca&gt;Mg&gt;Zn&gt;Cu. The highest content of Ca and Mg was found in goat milk. In the case of cow's milk, the content of Ca, Mg and Zn increased with increasing amount of milk fat in processed milk. Matrix correlation analysis showed that there is a significant correlation for the following pairs: Ca-Mg (r = 0.830), Zn-Cu (r = 0.799) and Ca-Zn (r = 0.624). Also, a strong correlation was found between milk fat and Ca, Mg and Zn (Pearson factor, r &gt; 0.600). Based on daily consumption of 200 mL of milk, the milk consumption does not meet the daily requirements for determined elements. Most significant intake was in case of Ca.

Effects of Ca addition on the microstructure and mechanical properties of Mg–Zn–Sn–Mn alloys

The effects of Ca addition on the microstructure and mechanical properties of Mg–Zn–Sn–Mn alloys were investigated in this study. The Mg–6Zn–4Sn–1Mn–xCa (x = 0, 0.2, 0.5, 1 and 2 wt%) alloys consist of the α-Mg, Mg2Sn, Mg7Zn3, MgZn, α-Mn, CaMgSn, MgZn2, Mg2Ca and Ca2Mg6Zn3 phases. With increasing Ca content, the eutectic phase and grains were refined, and the morphologies of the CaMgSn phases changed from point-like to needle-like, rod-like and lath-like. At room temperature, small amounts of Ca can improve properties owing to refinement strengthening. The two-stage aged Mg–6Zn–4Sn–1Mn–0.2Ca alloy has the best comprehensive properties at room temperature, with an ultimate tensile strength (UTS), yield strength (YS) and elongation of 407 MPa, 392 MPa and 6.2%, respectively. When the Ca content increased, the number of CaMgSn phases increased, and the morphologies coarsened. Further, it was a brittle phase, resulting in the deterioration of alloy properties. At high temperatures, a small amount of Ca can improve the high-temperature plasticity. The elongations of the as-extruded Mg–6Zn–4Sn–1Mn–0.2Ca alloy were 76.9% (150 °C) and 133.8% (200 °C). A high Ca concentration can significantly improve the high-temperature strengths because of the good thermal stability of the CaMgSn phases, the best UTS and YS are 160 MPa and 136 MPa, respectively, in as-extruded Mg–6Zn–4Sn–1Mn–2Ca alloy at 150 °C.

Bioaccessibility by perspiration uptake of minerals from two different sulfurous peloids

The risks associated with the use of peloids in thermal centers, spas, or at home, must be tested to develop appropriate safety guidelines for peloids formulations and the release of substances of high concern. Additionally, the beneficial effects of some elements on human health should be assessed to aid in interpreting the therapeutic action and effectiveness of pelotherapy on dermatological or osteomuscular disorders. Therefore, a methodology was developed to better understand the biogeochemical behavior of the elements in formulated peloids. Two peloids were formulated with the same clay and two different sulfurous mineral-medicinal waters for 90 days, with light stirring every 15 days. Bentonite clay, with a high content of smectite and Ca and Mg as the main exchangeable cations, and high heat capacity, was used. The selected mineral-medicinal waters were collected from two Portuguese thermal centers with recognized therapeutic efficacy for rheumatic, respiratory and dermatological pathologies. The peloids were used without drying and withdrawn directly from the maturation tank, and a mixture of bentonite and demineralized water was prepared as a reference sample. A stabilized, ready-to-use, artificial perspiration test was used to simulate the peloids’ interaction with skin. Thirty-one elements extracted from the two prepared peloids were analyzed using ICP-MS. The data were analyzed and related to the mineralogical composition of the original clay and supernatant composition of the maturation tanks. The content of some potentially toxic elements and metals’ bioaccessibility by perspiration showed very low solubility and undetectable amounts extracted from the studied samples. This analytical method provided reliable information on dermal exposure and the identification of some elements that may enter the systemic circulation, requiring implementation of surveillance and control measures.Graphical abstract

Elucidating the Interaction Mechanism of Mg(OH)2 and Ca(OH)2 under Enforced Carbonation

There is a potential for leveraging the synergy of carbonation of portlandite and Mg-based binders to improve the CO2 uptake, mechanical property, and thermodynamic stability of Mg- and Ca-based binders and enable its application. This work reports insights into the carbonation behavior of Mg(OH)2–Ca(OH)2 (MH–CH) mixtures including the precipitation of different carbonates, degree of reaction of each phase, mechanical properties, microstructure characterization, and thermodynamic stability. Results indicate that the compressive strength and degree of carbonation (DOC) of compacts increase first and then decrease with the increase of the Ca(OH)2 content. The compact containing 25% Ca(OH)2 yields the highest compressive strength of 91.4 MPa, while the compact containing 75% Ca(OH)2 has the highest DOC of 91.2%. The formation of nesquehonite with a lower density in compacts with lower contents of Ca(OH)2 (0 and 25%) results in a higher volume increase even at a very low DOC (14.2%), leading to a more densified structure in the compacts. Compacts with higher contents of Ca(OH)2 (50, 75, and 100%) precipitate calcite and magnesium calcite with higher thermodynamic stability than nesquehonite and improved water stability. Meanwhile, the high temperature in the initial stage of Ca(OH)2 carbonation causes severe water evaporation and insufficient water in compacts, thus restricting the continuous carbonation at the center having a lower DOC than the surface. The mixing of Mg(OH)2 and Ca(OH)2 significantly enhances the carbonation degree of both hydroxides, which may be explained by the complementation of Ca(OH)2 and Mg(OH)2 carbonation, in which the water released by the carbonation of Ca(OH)2 is bound to the crystal structure of hydrated magnesium carbonates (HMCs) from Mg(OH)2 carbonation.

Role of salts in fire extinguishing performance of aqueous film-forming foam (AFFF)

The active ingredients for aqueous film-forming foam (AFFF) are supplied as a concentrate, and the water used to dilute AFFF concentrates generally come from water sources around the fire site including seawater and river water. However, the effects of salt in water on fire-extinguishing performance of AFFF remain unclear. In this paper, we investigated the relationship between the interfacial properties, foam stability, and fire-extinguishing performance of three homemade AFFFs (nonionic AFFFAPG, amphoteric AFFFCAB and anionic AFFFSDS) and four commercial AFFFs. The seawater, firefighting water from different regions of China and deionized water were used to dilute AFFF concentrates. The results showed that AFFFAPG and AFFFCAB had a better performance than AFFFSDS in resisting the negative effects of salts on interfacial properties and foaming ability. In the fire-extinguishing tests, we found that dilution of AFFF with water samples containing high concentrations of Ca2+ and Mg2+ would weaken the fire-extinguishing performance. The traditional indicators characterizing the properties of foam (surface tension, liquid drainage rate, and spreading coefficient) could not explain the trend of fire extinguishing performance. The stability of AFFF in the presence of oil could be used to explain the difference in fire-extinguishing time of AFFF.

On the impact of grinding conditions in the flotation of semi-soluble salt-type mineral-containing ores driven by surface or particle geometry effects?

Grinding and flotation processes are often studied independently, despite the well-established grinding influence on flotation performance, which affects not only particle size and thus liberation but also shape and leads to complex changes in pulp chemistry affecting the particle surface properties relevant for selective bubble attachment. Yet, no study jointly investigated these possible causes and many are limited to single mineral flotation. We relate grinding conditions to changes in pulp chemistry and particle surface properties and assess their impact on upgrading. We studied three non-sulfide ores with different feed grades and valuables: scheelite, apatite, and fluorite. These were dry-, wet-, and wet conditioned-ground before flotation in a laboratory mechanical cell. Results were evaluated with bulk- and particle-specific methodologies. The selectivity of the process is higher after dry grinding for the fluorite and apatite ores and irrelevant for the scheelite ore. Variations in flotation kinetics of individual particles associated to their size and shape are not sufficient to explain these results. The higher concentration of Ca2+ and Mg2+ observed in the pulp after wet grinding, altering particle surface properties, better explains the phenomenon. Additionally, we demonstrate how particle shape impacts are system specific and related to both entrainment and true flotation.

Enhanced abundance of generalist and litter saprotrophs explain increased tropical forest soil carbon with long‐term nitrogen deposition

Abstract Nitrogen (N) deposition is a pervasive anthropogenic change that can alter the dynamics and storage of carbon (C) in tropical soils by altering the transformation of plant litter C to soil organic C (SOC). The response of fungi may be particularly important for explaining how N deposition affects SOC storage in tropical forests because they are the primary decomposers of plant litter. Fungi can be grouped into different ecological guilds, or functional groups, which often have contrasting responses to the same environmental change. However, little is known if shifts in fungal guilds and their functions explain increased tropical forest SOC storage under N deposition. We addressed this knowledge gap by assessing the effects of long‐term (6 years) experimental N addition (+N) on fungal guilds, their functions and SOC fractions in a tropical forest. Total SOC, dissolved organic C (DOC), particulate organic C and fungal necromass C were all higher in +N soils. The fungal community in +N soils was dominated by generalist saprotrophs, and leaf saprotroph abundance increased nearly 93‐fold compared to controls. These changes were accompanied by an increase in lignocellulolytic enzymes, indicating accelerated decomposition of recalcitrant litter C compounds. Chitosanase, which catalyses synthesis of glucosamine, was 1.37× higher in +N soils than controls; correspondingly, fungal necromass C contributed 1.42× more to SOC. Greater abundance of saprotrophic enzymes involved in organic acid synthesis in +N soils was associated with higher concentration of Ca2+ and DOC. We propose that N deposition increases SOC storage by enhancing saprotroph abundance and activity, whereby increased organic acid production supports fungal growth both directly and indirectly via the release of nutrients and DOC, resulting in greater inputs of necromass to the soil. Our findings highlight the importance of considering shifts in guild‐level fungal abundance and function to investigate changes in SOC dynamics and storage. Read the free Plain Language Summary for this article on the Journal blog.

Gellan gum-gelatin scaffolds with Ca2+ crosslinking for constructing a structured cell cultured meat model

As an emerging technology to obtain protein by culturing animal-derived cells in vitro, it is crucial to construct 3D edible scaffolds to prepare structured cell cultured meat products. In this study, a scaffold based on gellan gum (GG)-gelatin (Gel) was prepared and further cross-linked with Ca2+. FTIR confirmed the electrostatic interaction between GG and Gel and the ionic cross-linking of Ca2+ and carboxyl groups, and SEM images showed the porous structure of the scaffolds. The staining results showed that scaffolds with high concentrations of Ca2+ had higher biocompatibility than scaffolds with low concentrations of Ca2+ and non-crosslinked scaffolds, and scaffolds Ca2+-GG2-Gel3-0.5 adhered to more cells and were more conducive to cell spreading. The immunofluorescence staining, SEM images, Western blot, and RT-qPCR showed that the scaffolds supported the proliferation and myogenic differentiation of chicken skeletal muscle satellite cells (CSMSCs) and myotubes were formed on the scaffolds. Finally, the scaffolds were stained and fried after culturing. The results of the textural and chromatic analysis showed that the texture and color of the scaffolds were similar to fresh meat and meat products. These results showed that ionically crosslinked GG-Gel scaffolds are biocompatible and stable for structured cell cultured meat models.

Clogging mechanisms of biological aerobic filter in a petro-chemical wastewater treatment plant: A field study

Clogging reduces the treatment capacity of the Biological Aerobic Filter(BAF). Revealing the cause of clogging is the key to maintaining normal treatment of BAF. In a petrochemical wastewater treatment plant, two identical structure BAF exhibit different clogging situations. Pre-BAF was clogged with slurry while Posterior-BAF was clogged with medium hardening. SEM showed the medium granular of Posterior-BAF were glued by crystal scale. The crystal scale was detected as calcite by XRD. Water quality analysis illustrated that the raw water contained high concentrations of Ca2+ and HCO3−, the calcium carbonate solubility products of the Pre-BAF and Posterior-BAF water were 6.5 × 10−8 and 3 × 10−8, both are over deposition value. The concentration of TOC in the Pre-BAF influent water was 67.8 mg/L, 7 times higher than that in the Posterior-BAF. The calcium content in the Posterior-BAF scaling along the flow direction shows the proportions were 8.2 %, 19.1 % and 30.7 % in the front, middle and back sections respectively. Thermal gravimetric analysis of the crystalline scale illustrated there were organic weight loss peaks in the front section while only calcite peaks in the back section. It is concluded the organic content is the main reason for the clogging difference in the two BAFs. The organic substance exerts an effect on the scale composition and the calcite crystal perfect in the Posterior-BAF.