Addition Of MgCl2 Research Articles

Improving the sinterability of ZrC–SiC composite powders by Mg addition

High-density ZrC–SiC composite ceramics are typically sintered under demanding conditions, specifically, high sintering pressures and high temperatures. However, the need for such conditions can be alleviated by the use of ZrC–SiC composite nanoparticles with a high sintering activity. In the present study, core-shell-structured hybrid ZrC–SiC composite nanoparticles were synthesised with the addition of Mg by using a sol-gel process combined with in-situ carbothermal reduction reactions. The synthesis route, characterisation, and sintering mechanism were investigated in detail. It was found that the addition of MgCl2 to the precursors of ZrC–SiC can not only strengthen the network structure of ZrC–SiC gel but also lead to the formation of an amorphous Mg–Si–O oxide coating on the nanoparticle surfaces, which enhances the sinterability of ZrC–SiC nanoparticles. As a result, a compact ZrC–SiC composite ceramic with a higher relative density (up to 91.3%) than the contrast sample was successfully prepared by pressure-free sintering at 1700 °C.

Impact of different chloride salts and their concentrations on nitrification and trace gas emissions from a sandy soil under a controlled environment

AbstractPotassium chloride (KCl) and magnesium chloride (MgCl2) can be used to reduce carbon dioxide (CO2) and nitrous oxide (N2O) emissions, but their efficacy can be strongly affected by their Cl− concentration. This study aimed to compare the behaviour of different Cl− salts and concentrations with that of a typical commercial nitrification inhibitor (3, 4‐dimethylpyrazole phosphate, PIADIN). KCl, MgCl2 and PIADIN were investigated under a laboratory incubation experiment for two months. KCl and MgCl2 were applied at 0.5 and 1.0 g kg−1, while PIADIN was applied at 25 mg kg−1 soil. CO2 and N2O concentrations were analysed during the incubation period. The and dynamics in soil were also measured. The results showed 0.5 and 1.0 g kg−1 KCl and 0.5 g kg−1 MgCl2 decreased CO2‐C emissions by 43%–46% and increased N2O‐N emissions by 15%–48%, whereas 1.0 g kg−1 MgCl2 decreased CO2‐C emissions by 72% and N2O‐N emissions by 19%. KCl and MgCl2 retarded the decrease of the ‐N concentration and increase of the ‐N concentration. PIADIN reduced the emissions of CO2‐C by 113% and N2O‐N by 97% and maintained a high soil ‐N concentration and low ‐N concentration. MgCl2 addition at 1.0 g kg−1 was an effective treatment as the Mg both fertilized the soil and inhibited CO2‐C and N2O‐N emissions. Moreover, 1.0 g kg−1 MgCl2 could retard soil nitrification, the decrease of ‐N concentration and the increase of ‐N concentration. While PIADIN had no fertilizing value, it was a more effective nitrification inhibitor than Cl− salts.

Natural Transformation of Riemerella columbina and Its Determinants.

In a previous study, it was shown that Riemerella anatipestifer, a member of Flavobacteriaceae, is naturally competent. However, whether natural competence is universal in Flavobacteriaceae remains unknown. In this study, it was shown for the first time that Riemerella columbina was naturally competent in the laboratory condition; however, Flavobacterium johnsoniae was not naturally competent under the same conditions. The competence of R. columbina was maintained throughout the growth phases, and the transformation frequency was highest during the logarithmic phase. A competition assay revealed that R. columbina preferentially took up its own genomic DNA over heterologous DNA. The natural transformation frequency of R. columbina was significantly increased in GCB medium without peptone or phosphate. Furthermore, natural transformation of R. columbina was inhibited by 0.5 mM EDTA, but could be restored by the addition of CaCl2, MgCl2, ZnCl2, and MnCl2, suggesting that these divalent cations promote the natural transformation of R. columbina. Overall, this study revealed that natural competence is not universal in Flavobacteriaceae members and triggering of competence differs from species to species.

Effect of MgCl2 solution pretreatment on pubescens conversion at room temperature

Room temperature pretreatment of pubescens by soaking in MgCl2 aqueous solution with different concentrations was studied. The solid residues were analyzed by Van Soest chemical titration, XRD, FT-IR, and XPS, while the filtrates were analyzed by GPC, HPLC, ESI-MS, and 2D HSQC. The soaking by 20 wt% MgCl2 solution resulted in relatively higher conversion rates of both hemicellulose (8.3 wt%) and lignin (5.3 wt%). Trace amounts of glucose and xylose were obtained in the filtrates, and the amounts were hardly varied by the addition of MgCl2. However, compared with the filtrate from the sample pretreated by water, different oligomers were detected in the filtrates, indicating that MgCl2 might be able to change the mechanism of dissolution conversion of pubescens, meanwhile, no LCC was found, indicating that MgCl2 pretreatment could promote the breakage of ether linkage between carbohydrate part and lignin part in LCCs. A new monophenol (LIG9) might be obtained from LIG1, which might be attributed to the promoted breakage of β-O-4 in lignin by MgCl2 pretreatment. Compared with the sample pretreated by pure water, GPC analysis revealed that the proportion of larger compounds (Mn > 1700 Da) decreased while those of smaller compounds (Mn = 180-300, 300-800, and 800–1700 Da) all rose.

Synergistic effects of processing parameters on the biochemical and physical properties of tofu made from yellow field pea (Pisum sativum), as determined by response surface methodology.

Peas are an underutilized crop that do not require allergen labeling and are rarely genetically modified. Peas contain less protein than soy and vary in protein composition. Because peas contain more starch than soy and less lipids, an alternative procedure for pea tofu production needs to be developed to prevent excessive starch gelatinization while promoting curd development. To accomplish this, a response surface model design was utilized to determine optimal oil addition, cook time, and salt concentration. Treatment ranges were from 0.0% to 4.2% for oil addition, 60–134 min for cook time, and 5.0%–9.2% for MgCl2 addition. Treatments had varying effects on tofu texture. Cook time was directly proportional to the hardness and could be used to match the soft, firm, and extra firm texture targets of conventional soy tofu. Protein secondary structure was not related to gel strength, indicating a system with synergies between multiple components other than protein. This research will help satisfy the growing demand for alternatives to soy‐based foods.

Influence of microwave-assisted pyrolysis parameters and additives on phosphorus speciation and transformation in phosphorus-enriched biochar derived from municipal sewage sludge

Municipal sewage sludge is rich in phosphorus, the conversion of which into phosphorus-enriched biochar via microwave-assisted pyrolysis (MWAP) can realize the efficient treatment of municipal sewage sludge and the recycling of phosphorus. This follows the concepts of the sustainable development of waste management and “cleaner production”. At present, fundamental knowledge is lacking on the use of MWAP to recover phosphorus from municipal sewage sludge. In this study, the effect of MWAP parameters (temperature, power, and residence time) and additives on the properties of phosphorus-enriched biochar and the migration and transformation of phosphorus were investigated. The pH, surface area, and total phosphorous increased with increasing temperature and power, whereas a greater residence time promoted the conversion of non-apatite inorganic phosphorus (NAIP) into apatite inorganic phosphorous (AP). CaO addition promoted the conversion of NAIP into AP, whereas MgCl2 promoted the conversion of AP into NAIP. The simultaneous addition of CaO and MgCl2 led to antagonism, with CaO being dominant, demonstrating that the original phosphorus components prefer to combine with CaO. Phosphorus recovery was optimal at temperatures 500–600 °C and a residence time of 150 min. The addition of 9% CaO or 6% CaO +6% MgCl2 was sufficient to convert sewage sludge into phosphorus into AP. Under such conditions, AP contents in phosphorus-enriched biochar increased 1.4 times compared to that of additive-free biochar. Our study highlights the potential of MWAP for closing the phosphorus cycle and for producing fertilizers from complex materials, such as municipal sewage sludge.

Phosphorus recovery from wastewater using pyridine-based ion-exchange resins: Role of impregnated iron oxide nanoparticles and preloaded Lewis acid (Cu2+ ).

Inputs of P into receiving water bodies are attracting increasing attention due to the negative effects of eutrophication. Presently available P treatment technologies are unable to achieve strict P discharge limits from wastewater treatment plants (WWTPs) that may be as low as 10µg/L as P. Moreover, P is a nonrenewable resource and needs to be recycled in a closed-loop process for environmental sustainability. This article provides details of a process where a pyridine-based polymeric ion exchanger is modified with a combination of impregnated hydrated ferric oxide (HFO) nanoparticles and a preloaded Lewis acid (Cu2+ ) to effectuate selective P removal from wastewater and its recovery as a solid-phase fertilizer. Three such ion exchangers were studied: DOW-HFO, DOW-Cu, and DOW-HFO-Cu. Each of these materials displays selective phosphate affinity over competing anions chloride and sulfate, and also has the ability to be regenerated upon exhaustion to strip off the P in a concentrated solution. The P in concentrated regenerant can be recovered as struvite, MgNH4 PO4 , a slow-release fertilizer, after addition of MgCl2 and NH4 Cl. Results of equilibrium and kinetic studies and column experiments with synthetic solutions and a real WWTP effluent are discussed. PRACTITIONER POINTS: Fixed-bed columns with DOW-HFO, DOW-Cu, or DOW-HFO-Cu-can selectively remove phosphorus over competing anions. Fixed-bed columns of above-listed ion exchangers can produce an effluent P<6μg/L. DOW-Cu fixed-bed column ran for ≈500 Bed Volumes before breakthrough when fed Dartmouth WWTP secondary effluent. Regeneration of the exhausted DOW-Cu column resulted in ≈90% recovery of the phosphorus. Regenerant solution was used to generate high-purity crystals of magnesium ammonium phosphate, MgNH4 PO4 (struvite), a slow-release fertilizer.

Addition of calcium and magnesium chlorides as simple means of varying bound and precipitated minerals in casein micelle: Effect on enzymatic coagulation

In casein micelle (CM), Ca is either precipitated in the colloidal calcium phosphate (CCP) stabilized by clusters of phosphoserine (SEP) residues, or is directly bound to SEP (or glutamic and aspartic acids) of caseins without inorganic phosphate. However, it is currently not possible to titrate separately the different micellar Ca forms, making it difficult to assess their respective importance for CM properties and behavior. Both Ca2+ and Mg2+ have the same binding constants with SEP. Moreover, MgHPO4 is more soluble than CaHPO4, and its natural concentration in milk is lower. Thus, upon addition of MgCl2, Mg is mainly exchanged with CM in the bound form, whereas upon addition of CaCl2, Ca is mainly exchanged in the precipitated form. Our objective was to assess the role of the 2 forms of micellar cations (bound and precipitated) during the enzymatic coagulation of cow milk. Magnesium chloride, CaCl2, or KCl (10 mM) were added to milk and pH was adjusted to 6.6 after overnight equilibration. The KCl-supplemented milk was a positive control to assess the effect of the increased ionic strength after MgCl2 and CaCl2 addition. Mineral partition between soluble and colloidal phases after salt addition was assessed both experimentally and by using computer simulation. Enzymatic coagulation was proceeded at 30°C. Hydrolysis of κ-casein was followed by the quantitative determination of caseinomacropeptide released by RP-HPLC, aggregation of para-κ-casein micelles was measured through the evolution of backscattering properties of milk and the gel time and gel firming kinetics were determined using a Chymograph (Chr. Hansen, Horsholm, Denmark). The KCl addition did not affect mineral partition. As expected, CaCl2 addition mainly increased the CCP content, whereas the addition of MgCl2 mainly increased the bound divalent cations content. The kinetics of κ-casein hydrolysis was slowed down after CaCl2 and MgCl2 addition, and was negatively correlated with the concentration of divalent cations in the soluble phase of milk. Aggregation and gel firming curves plotted versus the progress of κ-casein hydrolysis were similar for both CaCl2- and MgCl2-supplemented milk. In view of the dual-binding model for CM assembly, this means that both Ca forms reduce electronegative repulsions between para-micelles by specific charge shielding. Inclusion of 2 Ca forms in structural models for CM allows a more detailed comprehension of how mineral equilibria affect CM properties.

Coupling biogas recirculation with FeCl3 addition in anaerobic digestion system for simultaneous biogas upgrading, phosphorus conservation and sludge conditioning

The high costs involved in sewage sludge treatment and disposal in wastewater treatment plants (WWTPs) not only bring about improper sludge disposal and thus environmental pollutions, but also limit the investment on construction of WWTPs, especially in rural areas or low-income regions. This comparative study examined the effect of biogas recirculation coupled with chemical addition in a semi-continuous anaerobic digester for sludge treatment, which was proven to achieve biogas upgrading, phosphorus conservation and sludge conditioning simultaneously, largely reducing the sludge treatment cost. Results show that FeCl3 addition coupling biogas recirculation can improve sludge dewaterability by 94% in comparison to 75% by equivalent MgCl2 addition, and 97% phosphorus in digestate can be conserved in solid with formation of vivianite-like crystals. Biogas recirculation can enhance CH4 yield and content by 13% and 11%, respectively, likely attributable to the increased relative abundances of both hydrogenotrophic Methanomicrobiales and acetoclastic Methanosarcinales.

Composition-dependent microstructure evolution in liquid MgCl2-KCl: A first-principles molecular dynamics study

The structural evolution of MgCl 2 -based materials is of considerable interest due to their current and potential applications in numerous technologies, such as electrolyte in magnesium electrolysis, secondary coolant for high-temperature reactors, and a new generation heat transfer fluid for concentrated solar power systems. However, their intrinsic feature is poorly understood and difficult to obtain with experimental techniques. In this work, first-principles molecular dynamics simulations (FPMD) are adopted to investigate the structural evolution of molten MgCl 2 -KCl fused salt. Examination of the radial distribution function, probability distribution of coordination numbers and bond angle distribution of the melts reveals that the local geometry of the Mg converts from mainly tetrahedral to a distorted octahedral with one-two anion vacancies as the concentration of MgCl 2 is increased. Accompanied by this structural change, there are also corresponding variations in the stability and dynamics of the system. Further analysis of the stability and the lifetime of the Mg Cl bond indicate that the coordinated Cl − anions around Mg 2+ cations are more dynamic in MgCl 2 richer compositions. Moreover, this study shows that the addition of MgCl 2 will inhibited the formation of isolated structural units and promote the extension of Mg chains. In conclusion, the simulations successfully reproduce the structural features of MgCl 2 -KCl melts and highlight the application prospects of FPMD simulations in revealing the local structure of molten salts. • FPMD simulations are employed in the investigation of molten MgCl 2 -KCl. • The evolution of the local geometry of the Mg 2+ first coordination shell is revealed. • The the coordinated Cl − anions around Mg 2+ cations are more dynamic in MgCl 2 richer compositions. • The addition of MgCl 2 will inhibited the formation of isolated structural units and promote the extension of Mg chains.

Effect of EDTA on measurement of cortisol and thyroxine by chemiluminescent enzyme immunoassay in dogs.

The addition of ethylenediamine tetra-acetic acid (EDTA) to serum can affect the measurement of cortisol by chemiluminescent enzyme immunoassay (CEIA); addition of magnesium chloride (MgCl2) may reverse the effects. However, similar characteristics for thyroxine (T4) measurement are unknown. We measured cortisol and T4 in paired EDTA-anticoagulated plasma and serum samples from 50 dogs. Additionally, both hormones were measured in 15 samples of each type after the addition of MgCl2. Samples were collected under routine clinical conditions; therefore, specific EDTA concentrations in plasma samples were unknown. Cortisol and T4 values were significantly different comparing plasma and serum samples in the absence of MgCl2. For cortisol and T4, EDTA-plasma concentrations were 51.2% and 43.7% higher than serum, respectively (p < 0.001 for both). The addition of MgCl2 to plasma significantly decreased the measured cortisol concentrations (p < 0.001) but not T4 (p = 0.44). After addition of MgCl2, cortisol concentrations in EDTA-plasma were no longer significantly different from serum, whereas T4 concentrations in EDTA-plasma remained significantly different from serum. In the clinical setting in which tubes may be underfilled, use of EDTA-plasma significantly increases the measured concentration of cortisol and T4 obtained by CEIA. Addition of MgCl2 to EDTA-plasma can overcome the effects of EDTA when measuring cortisol, but not T4. Thus, T4 should not be measured in EDTA-plasma.

Influence of chemical additive on the physical and mechanical properties of cement-bonded composite panels made from jute stick

The aim of the study was to observe the effects of chemical additives (calcium chloride (CaCl2) and magnesium chloride (MgCl2)) on the setting time of jute stick cement-bonded composites (CBCs). The setting time was judged based on the measured physical and mechanical properties of the composites as function of the press time. The mixing ratio of jute stick particles, cement and water was set at 2:1:1 for chemical additive (CaCl2/MgCl2) incorporated composites, and a controlled one without additive was manufactured based on jute particles and cement mixing ratio of 2:1. Three concentration levels of 6, 8 and 10% of CaCl2 and MgCl2 were used separately to produce the composite boards. In this study, the composite mixtures were cold-pressed at a pressure of 5 MPa and different pressing duration of 4, 6, 8, 12 and 16 h. Incorporation of the additives reduced the press time, and higher percentage of additives increased the physical and mechanical properties of the composite panels produced. Composite panels made with MgCl2 exhibited better performance compared with those made with CaCl2. The highest modulus of elasticity (MOE) and modulus of rupture (MOR) of the manufactured samples were 10.5 and 4595 MPa, respectively for the maximum percentage of MgCl2 addition with 6 h press time. It appears that these additives especially MgCl2 decreased the setting time of the CBCs, which can be considered as an alternative approach for the industry to produce CBCs in shorter time.

Isotype Heterojunction Solar Cells Using n-Type Sb2Se3 Thin Films

The carrier-type of the emerging photovoltaic Sb2Se3 was evaluated for both thin films and bulk crystals via a range of complementary techniques. X-ray photoelectron spectroscopy (XPS), hot probe, Hall effect, and surface photovoltage spectroscopy showed films and crystals synthesized from the Sb2Se3 granulate material to be n-type with chlorine identified as an unintentional n-type dopant via secondary ion mass spectrometry analysis. The validity of chlorine as a dopant was confirmed by the synthesis of intrinsic crystals from metallic precursors and subsequent deliberate n-type doping by the addition of MgCl2. Chlorine was also shown to be a substitutional n-type shallow dopant by density functional theory calculations. TiO2/Sb2Se3 n–n isotype heterojunction solar cells with 7.3% efficiency are subsequently demonstrated, with band alignment analyzed via XPS.

Effects of typical alkaline earth metal salts on cellulose torrefaction: Solid products and thermal gravimetric analysis

To investigate the influencing mechanisms of calcium and magnesium on the solid products of biomass torrefaction, cellulose was selected as the feedstock in this article. The experiments were conducted in the holding temperature range of 200 °C to 300 °C under the atmosphere of nitrogen. Based on the impregnation methods (chlorides, hydroxides, and acetates of Ca and Mg), the results showed that the solid product yield of torrefacted cellulose impregnated with calcium or magnesium salts was lower than that of raw cellulose torrefaction at 200 °C to 275 °C. However, at 300 °C, the solid product yield of impregnated cellulose torrefaction was higher. During torrefaction, the CaCl2 had a stronger effect than other calcium salts. The Mg(CH3COO)2 had less of an effect than other magnesium salts. The crystallinity of the torrefied cellulose with impregnated calcium or magnesium salts was considerably reduced from 51.1% (raw cellulose) to 7.7% (addition of CaCl2), 34.8% (addition of Ca(OH)2), 28.6% (addition of Ca(CH3COO)2), 9.2% (addition of MgCl2), 13.6% (addition of Mg(OH)2), and 12.0% (addition of Mg(CH3COO)2). The results of the thermal gravimetric analysis showed that the impregnated calcium or magnesium salts dramatically reduced the activation energy of the torrefaction.

Product and cost perspectives of phosphorus recovery from human urine using solid waste ash and sea salt addition – A case of Thailand

Phosphorus (P) recovery from human urine was evaluated using the addition of MgCl2, sea salt and solid-waste (SW) incinerated ashes. The study objectives were to assess and compare their efficiency for P recovery, costs of chemicals added and relevant crystal characteristics. Results from the experiments conducted between pH range of 7–11 revealed that P precipitation efficiency was increased to 89–97% and 72–88% when MgCl2 and sea salt were added, respectively. Precipitates obtained from both cases were found to contain 10.8–17.1% P dry weight which is superior to commercial fertilizer (8.80% P). Based on SEM-EDS examination and chemical equilibrium thermodynamics, about 83% and 68% of precipitates were in the form of struvite for the addition of MgCl2 and sea salt, respectively. Although 18% less struvite was formed with sea salt added, cost was found to be reduced from 4.07 USD·(kg P)−1 for MgCl2 addition to 2.91 USD·(kg P)−1 using sea salt addition, representing a 28% cost reduction. Furthermore, SW ashes added into the urine increased P recovery efficiency about 6–17%. Addition also lowered the costs to 1.75 and 1.68 USD·(kg P)−1 for SW fly ash and bottom ash, respectively. Thus, ash addition reduced cost and provided an alternative to landfill disposal. However, addition of SW bottom ash might result in recovered P solids with lead concentration exceeding the EC limit for inorganic fertilizer. In summary, results of this study have demonstrated a pragmatic way to recover P from human urine with the use of sea salt and ash as alternative Mg source and seed. Results indicate that this practice not only produces a good-quality fertilizer as struvite for sustainable P management, but also helps protect the water environment, and support circular economy of P in human ecosystem.

Corrosion performance of steel reinforcement in concrete admixed with magnesium chloride and sulphate

PurposeBesides with a large amount of Na+and Cl−ions in seawater, the presence of Mg+2and SO4−2ions builds more complex corrosion mechanism. This paper aims to investigate the corrosion of embedded reinforcement in concrete with the environment of both Cl−and SO4−2anions associated Mg+2cation.Design/methodology/approachThe concrete specimens were prepared by using ordinary Portland cement (OPC), and OPC blended with metakaolin (MK) for water to cementitious material ratio (w/cm) 0.48 and 0.51. The concrete mixes were contaminated with the addition of MgCl2alone and combined MgCl2and MgSO4in mix water. Reinforcement corrosion was evaluated by half-cell potential and corrosion current densities (Icorr) at regular intervals. Moreover, the influence of cementitious material type, salt type and w/cm ratio on electrical resistivity of concrete was also investigated. The statistical models were developed for electrical resistivity as a function of calcium to aluminium content ratio, compressive strength, w/cm ratio and age of concrete.FindingsAlthough the corrosion initiation time increases in the concomitant presence of MgSO4and MgCl2as internal source compared to MgCl2, Icorrvalues are higher in both OPC and MK blended concrete. However, electrical resistivity decreased with addition of MgSO4. MK blended concrete performed better with increased resistivity, corrosion initiation time and decreased Icorrvalues.Originality/valueThis study reports statistical distributions for scattered Icorrof rebar in different concrete mixtures. Stepwise regression models were developed for resistivity by considering the interactions among different variables, which would help to estimate the resistivity through basic information.

Effect of alkaline earth metal chloride additives BCl2 (B = Mg, Ca, Sr and Ba) on the photovoltaic performance of FAPbI3 based perovskite solar cells.

Additive engineering is known to be an effective method for inducing a simultaneous effect of enlarging the grain size and surface passivation. As compared to the monovalent halides frequently used as additives, divalent halides are relatively less investigated in the role of additives. In this work, we report effects of alkaline earth metal halides BCl2 (B = Mg, Ca, Sr, Ba) as additives on the opto-electronic properties and photovoltaic performance of FAPbI3 based perovskite solar cells (PSCs). A significant improvement in power conversion efficiency (PCE) from 17.27% to 21.11% is observed by MgCl2 addition in the FAPbI3 precursor solution, while a marginal increment for CaCl2 or BaCl2 and a negative effect for SrCl2 is observed. The lattice constant of cubic FAPbI3 is hardly changed by additives, while the crystallinity is improved by MgCl2. The carrier lifetime increases from 40 ns to 287 ns and the trap density is reduced from 1.08 × 1016 cm-3 to 3.19 × 1015 cm-3 by addition of 5 mol% MgCl2, which is responsible for the enhancement in photovoltaic parameters. The steady-state PCE of the PSC with the MgCl2-additive-treated FAPbI3 measured under continuous illumination at the maximum power point remains unchanged for 1500 s.

Structural transitions of sword bean canavalin in response to different salt concentrations

Canavalin is the major storage protein in sword beans (Canavalia gladiata) and belongs to the 7S seed globulin class. Canavalin solubility can be reversibly altered via the addition of MgCl2 and CaCl2 at different concentrations; specifically, it is insoluble at lower concentrations and soluble at higher concentrations. However, the addition of NaCl does not induce the insolubilization of canavalin. In this study, it was determined that the addition of NaCl causes the nearly complete solubilization of MgCl2-precipitated canavalin in the presence of high concentrations. Moreover, using gel filtration we examined the quaternary structures of soluble canavalin in the bean extract and in the presence of high-concentration salts. Results indicated that canavalin was present in the monomer form within crude extracts with distilled water. Alternatively, we identified trimeric soluble canavalin in the presence of high concentrations of NaCl or MgCl2. Our study revealed that the quaternary structures of sword bean soluble proteins differ in crude extract compared to those in high-concentration salt solutions. The three-dimensional structure of β-conglycinin, which is a typical 7S-seed globulin in soybean, has a trimer form in the presence of high concentrations of NaCl. However, it remains unclear whether β-conglycinin is present as trimers in soybean seed. Our findings serve as an important reference to analyze 7S globulin characteristics.

Chlorine Addition to Existing Zinc Fuming Processes: A Thermodynamic Study

Zinc fuming processes are used to volatilize heavy metals from slags and produce a clean slag. Since alternative fuel sources containing plastics are explored, the effect of chlorides becomes relevant. In this paper, the influence of Cl additions to a zinc fuming process on the Zn volatilization is investigated. Thermodynamic calculations were carried out on available industrial data from three different installations. The effects on the fuming performance of the α-value (mol O2/ mol C, in a range of 0.5 to 0.75), chloride source (Cl2, KCl, NaCl, MgCl2, and CaCl2), and added chloride amounts (50, 150, and 500 ppm Cl/min) were investigated. Although the α-value is still the most influential parameter for the overall zinc fuming rate, chloride additions can have positive effects as well. They make ZnCl2 volatilization possible, which supplements the Zn volatilization. Large additions of CaCl2 and MgCl2 improve the fuming rate the most since they cause the largest formation of the volatile ZnCl2 and they do not negatively influence Zn volatilization.

A novel anaerobic digestion system coupling biogas recirculation with MgCl2 addition for multipurpose sewage sludge treatment

Sewage sludge, one of the major byproducts from wastewater treatment plants (WWTPs), contains high contents of nutritional elements that can be recycled and reutilized to make up the overuse of limited resources on Earth. Currently, the reutilization ratio of sewage sludge is relatively low, most probably due to the high operation costs for its treatment and disposal in WWTPs. This study for the first time realized biogas upgrading, resources conservation and sludge conditioning simultaneously in one anaerobic digestion (AD) reactor for sewage sludge treatment through coupling biogas recirculation with MgCl2 addition. Results showed that 86% of methane content could be obtained by the intermittent biogas recirculation during AD. When MgCl2 was further added, soluble orthophosphate and ammonia nitrogen were reduced by 87% and 19% during 17 days’ AD. At the same time, around 120 mg/g-total solids (TS) of struvite was estimated to generate in the digested sludge, and the sludge dewaterability was enhanced by 37% when biogas recirculation was performed along with MgCl2 addition. At last, not only the enhanced electricity generation from biogas with higher methane content but also the increased fertilizer potential of the digestate were analyzed in the context of a local WWTP, reflecting the great potentials and profits of this novel AD system in industrial-scale sewage sludge treatment.