Amount Of Fe3 Research Articles

The network structure and properties of a unique mining solid waste-based glass-ceramics

To alleviate the environmental pollution caused by the stockpile of mining-based, such as coal-based solid waste, mining solid waste-based CaO-MgO-Al2O3-SiO2 (CMAS) glass-ceramics with a diopside phase as the main crystalline phase was developed by one-step sintering method, and the effect of different solid waste content on the network structure and properties were investigated. The results show that, with the diversification of solid waste content, the crystallization temperature (Tp), the amount of Fe3+ concentration, and diopside crystalline, the main structure of glass Q2 changed also. Accordingly, significant changes have occurred in properties such as the bending strength, Vickers hardness, and density. Optimizing the raw material ratio, crystallization mechanism, a mining solid waste-based glass-ceramic with unique network structure is well developed and the bending strength, Vickers hardness, fracture toughness, and density reaches maximum values of 175.19 MPa, 10.47 GPa, 2.03 MPa m1/2, and 3.00 g/cm3, respectively. The findings contribute significantly to the development of durable and reliable materials for the utilization of mining solid waste resources.

Mechanochemically assisted synthesis, inversion degree and magnetization of spinel compounds across the (Zn,Mg)Fe2O4 system for flexible smart devices

Magnetic spinel oxides are multifunctional materials used or under consideration for a range of applications across electronics, communication technologies, remediation and health. They can also present high magnetostriction coefficients, and are being investigated as active inorganic fillers in polymer matrix composites for flexible sensors and actuators. However, state-of-the-art materials for these later applications are NiFe2O4- and CoFe2O4-based compositions, and it is necessary to find environmentally-friendly alternatives free of toxic elements that provide comparable responses, ideally biocompatible. This work presents a study of the spinel phases across the (Zn,Mg)Fe2O4 system and of their suitability to be used as magnetic component in hybrid composites. Spinel single phase materials with variable particle size across the submicron range, down to the verge of the nanoscale, have been obtained by mechanochemically assisted synthesis for five selected compositions spanning the whole ZnFe2O4-MgFe2O4 system. Evolution of the crystal lattice and inversion degree (amount of Fe3+ at tetrahedral site) has been obtained from Rietveld refinement of synchrotron X-ray diffraction data, and correlated with the development of magnetic ordering. Ferrimagnetic compositions are identified, among which Zn0.25Mg0.75Fe2O4 stands out for its magnetization characteristics comparable to NiFe2O4. This spinel compound is thus a promising environmentally-friendly candidate for flexible devices, in principle also biocompatible.

Photocatalytic degradation of the remazol red ultra RGB dye using SrFe12O19-Fe3O4 magnetic oxides dispersed in silica: Effect of reduction temperature

Dyes are the most frequently discarded industrial wastes in aquatic ecosystems, among which Remazol Red ultra RGB stands out. In this context, magnetic iron-based catalyst dispersed in silica were prepared by Pechini route as an alternative for the photodegradation of Remazol Red Ultra RGB. The XRD and Mössbauer spectroscopy results indicated the formation of a magnetic material that, after reduction treatment with H2, forms a magnetite phase combined with Sr hexaferrite dispersed in amorphous silica. The TPR-H2 profiles indicated the reduction of Fe3+ to Fe2+ within the considered temperature range, the amount of Fe2+ increased with rising temperature. The SEM images showed sponge-like morphology for the samples. The EDS spectra and mapping confirmed a high uniformity in the distribution of active iron species in the silica. The magnetic measurements showed a lower magnetic signal for the sample reduced at 600 °C, due to the lower magnetic moment of Fe2+ formed after the reduction. The diffuse reflectance spectra showed a main absorption region between 500 and 200 nm and the estimated band-gap values were of 1.4 and 1.9 eV for the reduced sample and the fresh oxide, respectively. The surface charge was obtained via zeta potential, demonstrating good stability under pH changes and reaching a negative potential in the pH range from 2 to 6. The photocatalytic tests showed that the samples with higher content of Fe2+ demonstrated a greater photocatalytic degradation of the Remazol Red Ultra RGB dye, reaching 100 % degradation in 1 h for the solid reduced at 600 °C. A plausible mechanism for the photodegradation of Remazol Red Ultra RGB was proposed, considering the different elementary steps involving the participation of iron sites and the formation of oxidant radicals.

Facile preparation of fluorescent tartaric acid-modified polymer dots for Fe3+ detection

Herein, fluorescent polymer dots (T-PDs) with excellent properties were synthesized through a facile magnetic stirring method using carboxymethyl cellulose derivative (CMC-NH2) and tartaric acid (TA). The synthesized T-PDs exhibit a nanoscale structure, excellent stability and good fluorescence behavior with a fluorescence quantum yield of 12.5 %. Moreover, the T-PDs can be selected for the design of sensors for detecting Fe3+ via the internal filtration effect (IFE) through a fluorescence quenching process. A good linear equation can be fitted between (F0-F/F0) and the amount of Fe3+ from 0 to 600 μM (R2 = 0.998) and the detection limit (LOD) for Fe3+ was determined to be 0.74 μM (3σ/slope). Additionally, the as-prepared sensing platform can be utilized for detecting Fe3+ in real samples, which indicates its great potential for application in sensing. Interestingly, the fluorescence of the quenched system can be partially recovered by the addition L-cysteine. Thus, a fluorescent “ON-OFF-ON” switch can be designed, and a resettable and multireadout logic gate operation can be realized.

Effect of Fe(III) on soybean protein-gallic acid hydrogel: Structure, functional properties, and digestive properties

A soy protein isolate-gallic acid (SPI-GA) complex was synthesized, mediated using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide. Different amounts of Fe3+ were then added to the SPI-GA complex to produce hydrogels (SPA@Fe) containing metal-phenolic network without heating the protein. Spectral analysis revealed that these hydrogels contained multiple modes of cross-linking, such as Schiff bases, hydrogen bonds, and coordination bonds. Coordination bonds formed between GA and Fe3+ mainly had a coordination number of three, and they changed the structure of the protein. Furthermore, these coordination bonds also endowed SPA@Fe with a more compact crosslinked network, thus improving the hydrogel's textural characteristics, thermal stability, storage modulus, and glucose adsorption capacity. The SPA@Fe hydrogel exhibited the best performance when the molar ratio of GA to Fe3+ was 1, with the thermal stability, hardness, springiness, and glucose adsorption capacity being 3.9, 1.84, 1.22, and 1.93 times higher than those of the SPI-GA hydrogel, respectively. Moreover, in-vitro digestion tests showed that SPA@Fe could control the release of loaded curcumin, had good capacity for adsorbing bile salt, and showed delayed degradation. This hydrogel system may offer a safe and feasible way to deliver bioactive substances such as curcumin.

Perovskite CoSn(OH)6 nanocubes with tuned d-band states towards enhanced oxygen evolution reactions.

The CoSn(OH)6 perovskite hydroxide is a structure stable and inexpensive electrocatalyst for the oxygen evolution reaction (OER). However, the OER activity of CoSn(OH)6 is still unfavorable due to its limited active sites. In this work, an Fe3+ doping strategy is used to optimize the d-band state of the CoSn(OH)6 perovskite hydroxide. The CoSn(OH)6 catalyst with slightly Fe3+ doped nanocubes is synthesized by a facile hydrothermal method. Structure characterization shows that Fe3+ ions are incorporated into the crystal structure of CoSn(OH)6. Owing to the regulation of the electronic structure, CoSn(OH)6-Fe1.8% exhibits an OER overpotential of 289 mV at a current density of 10 mA cm-2 in OER electrochemical tests. In situ Raman spectroscopy shows that no obvious re-construction occurred during the OER for both CoSn(OH)6 and CoSn(OH)6-Fe1.8%. DFT calculations show that the introduction of Fe3+ into CoSn(OH)6 can shift the d-band center to a relatively high position, thus promoting the OER intermediates' adsorption ability. Further DFT calculations suggest that incorporation of an appropriate amount of Fe3+ into CoSn(OH)6 significantly reduces the rate-determining Gibbs free energy during the OER. This work offers valuable insights into tuning the d-band center of perovskite hydroxide materials for efficient OER applications.

Analysis of Cation Composition in Dolomites on the Intact Particles Sampled from Asteroid Ryugu.

Characterization of the elemental distribution of samples with rough surfaces has been strongly desired for the analysis of various natural and artificial materials. Particularly for pristine and rare analytes with micrometer sizes embedded on specimen surfaces, non-invasive and matrix effect-free analysis is required without surface polishing treatment. To satisfy these requirements, we proposed a new method employing the sequential combination of two imaging modalities, i.e., microenergy-dispersive X-ray fluorescence (micro-XRF) and Raman micro-spectroscopy. The applicability of the developed method is tested by the quantitative analysis of cation composition in micrometer-sized carbonate grains on the surfaces of intact particles sampled directly from the asteroid Ryugu. The first step of micro-XRF imaging enabled a quick search for the sparsely scattered and micrometer-sized carbonates by the codistributions of Ca2+ and Mn2+ on the Mg2+- and Fe2+-rich phyllosilicate matrix. The following step of Raman micro-spectroscopy probed the carbonate grains and analyzed their cation composition (Ca2+, Mg2+, and Fe2+ + Mn2+) in a matrix effect-free manner via the systematic Raman shifts of the lattice modes. The carbonates were basically assigned to ferroan dolomite bearing a considerable amount of Fe2+ + Mn2+ at around 10 atom %. These results are in good accordance with the assignments reported by scanning electron microscopy-energy-dispersive X-ray spectroscopy, where the thin-sectioned and surface-polished Ryugu particles were applicable. The proposed method requires neither sectioning nor surface polishing; hence, it can be applied to the remote sensing apparatus on spacecrafts and planetary rovers. Furthermore, the non-invasive and matrix effect-free characterization will provide a reliable analytical tool for quantitative analysis of the elemental distribution on the samples with surface roughness and chemical heterogeneity at a micrometer scale, such as art paintings, traditional crafts with decorated shapes, as well as sands and rocks with complex morphologies in nature.

The impact of Fe2+ and Na+ concentrations on hydrogen production with three different fermenter bacteria

Batch experiments were conducted to investigate the effects of Fe2+ and Na+ on the hydrogen (H2) production performance from three different metabolic type hydrogen-producing bacterial strains. The appropriate amount of Fe2+ significantly promoted the H2 production of all three hydrogen-producing bacteria. The combination of H2 production and liquid products showed that Fe2+ was more suitable for the H2 production and metabolism of E. harbinense ZGX4. When the Fe2+ concentration was 0.05 g/L, the H2 production and liquid products concentrations were 2170 mL/L-medium and 6530 mg/L, respectively. Na+ enhanced the H2 production of E. harbinense ZGX4 and C. butyricum 1.209 but inhibited the H2 production of E. cloacae 1.2022. Na+ made C. butyricum 1.209 exhibit the best H2 production and metabolic performance when the Na+ concentration was 2 g/L, while the H2 production, and liquid products concentration were 2460 mL/L-medium and 5350 mg/L, respectively. At the end of the experiment, it was found that the addition of Fe2+ could change the type of fermentation in C. butyricum 1.209. Therefore, further exploration of the effects of other metal ions on model hydrogen-producing strains has great potential for achieving high hydrogen production rates, among other things.

A decrease in the Fe3+/∑Fe ratio of bridgmanite with temperature at the top of the lower mantle

Bridgmanite, the most abundant mineral in the lower mantle, readily incorporates Fe3+ even under very reducing conditions where it is in equilibrium with metallic iron. This has led to the proposal that charge disproportionation of Fe2+ to produce Fe3+ and metallic iron may occur in the lower mantle. The amount of Fe3+ in bridgmanite is important for understanding the oxidation state of the mantle, as charge disproportionation of Fe2+ to form Fe3+ and metallic iron, followed by loss of metallic iron to the core, could have raised the Fe3+ content of the mantle as a whole after core formation. Here, the Fe oxidation state in bridgmanite was studied as a function of temperature at 27 GPa and an oxygen fugacity of ∼2.0 log units above the iron-wüstite oxygen buffer (ΔIW+2) using multi-anvil techniques. Bridgmanite Fe3+/∑Fe ratios were determined by Mössbauer spectroscopy and decrease from ∼80% at 1800 K to 50% at 2600 K. A decreasing Fe3+/∑Fe ratio with increasing temperature indicates that the level of charge disproportionation would have been lower under the higher temperature conditions of the early Earth. However, if the redox state of the upper lower mantle is buffered by coexisting iron and ferropericlase, then the relative oxygen fugacity will have changed very little during secular cooling.

Reversible Fe3+-induced urushi organogels in gamma butyrolactone

A multinetwork structured urushi organogel was created using low-volatility gamma butyrolactone (GBL) solvent and Fe3+ ions. The urushi organogels were fabricated through chemical crosslinking with the oxidative polymerization of urushiol as well as physical crosslinking due to the coordination bonds with Fe3+ ions in the Fe3+/urushiol/GBL solution. The role of Fe3+ ions is to provide physical crosslinking sites via the coordination bond with the catechol functional moiety of urushiol and also to serve as the catalysts for the polymerization of urushiol. The gelation and characteristics of urushi organogels in GBL with different amounts of Fe3+ ions were investigated. The formation of urushi organogel by chemical crosslinking and physical coordination crosslinking was investigated by FT-IR, Raman spectroscopy and X-ray photoelectron spectroscopy.The presence of a physical coordination bond between the Fe3+ ion and the catechol moiety of urushiol provides reversible adhesive properties, which provide consistent tensile strength after reattaching the urushi organogel film. The stretchability as well as the reversibility in mechanical strength can provide the possibility for various applications of eco-friendly natural urushi. This research provides not only a method to prepare multinetwork natural urushi organogels using Fe3+ ions but also the great possibility of expanding the application area of natural urushi(ol)s.

Changes in color and iron ions of commercial iron gall inks after artificial aging

Iron gall inks consist of vitriols (sulphates of certain metals), gall nut extracts; and gum Arabic: after exposure to oxygen, dark-colored compounds of the inks are formed. As the complexity of the composition of iron gall inks renders documents susceptible to environmental influences, this causes the handwriting thereon to fade. These add technical difficulties to the protection of iron gall inks. Therefore, it is particularly important to understand the changes in the inks during the aging process. For this reason, iron gall ink-stained paper specimens were subject to an intense analytical program to investigate their chemical and physical modifications after aging (temperature/humidity, temperature, and ultraviolet light aging), commercial iron gall ink was used for this experiment, making the study more applicable. The changes of iron gall inks were evaluated using color variation, color density, absorbance, and X-ray photoelectron spectroscopy (XPS). All results indicate that the temperature, humidity, and UV are harmful to the inks in both physical and chemical terms. Physical damage is mainly the aging of the ink color lightening, color density decreases, of which the color of the samples treated with damp heat for 30 days undergoes the greatest change. The chemical change is represented by the ratio of the concentration of iron ions in different valence states, the amount of Fe3+ in the untreated inks is much greater than that of Fe2+, and the amount of Fe2+ exceeds that of Fe3+ after exposure to different methods of aging. Experiments show that UV light causes the most severe damage to handwriting. The main manifestation thereof is color-fade and the paper surface ink part of the iron ion content changes, with the increase of aging time, the Fe2+ content gradually increases. This experimental study of the changes produced by iron gall inks during aging can provide better technical support for the protection of the ink handwriting.

Determination of Se and Te by hydride generation-inductively coupled plasma mass spectrometry after mixed-acid digestion of tungsten ores

Se and Te in tungsten ores are important parameters for exploring the metallogenetic process of tungsten ores; however, due to their high refractory, low abundance, extreme volatilization, as well as the complex matrix interference during analysis, it is a challenge to accurately determining their concentrations in tungsten ores. This study presents a method of combining hydride generation device with inductively coupled plasma mass spectrometry (HG-ICP-MS) to determine the contents of Se and Te in tungsten ores. As a pre-processing step, tungsten ores were dissolved in the mixture of HF + HNO3 + HClO4 and microwaved for digestion. The analytical results show that the main matrix components (K, Na, Ca, Mg, Fe, Mn and Pb) in tungsten ores have no interference, and the interference of W, Cu, Zn and Bi can be eliminate by adding an appropriate amount of Fe3+. The method was used to test 6 samples with different tungsten concentrations. Compared with the results of hydride generation atomic fluorescence spectrometry (HG-AFS) method, the mean values of HG-ICP-MS method showed a good consistency and the relative mean deviations of Se and Te contents were in the range of −5.2%­ to 6.2% and − 3.8%­ to 3.4%, respectively. The values of Se, Te and Te/Se ratio determined from various geological samples (30 soil and sediment samples, 30 granite samples, 25 poly-metallic sulfide ore samples and 29 tungsten ore samples) highlight their potential prospecting in the metallogenetic process of tungsten ores.

Mussel-inspired ferric ion-polydopamine complex as a facile, green and efficient platform to functionalize carbon fiber for improving interfacial adhesion of composites

A mussel inspired co-deposition of ferric ion-polydopamine (PDA) is explored and constructed on carbon fiber via facile dip-coating strategy for the first time to realize the enhancement in interfacial adhesion of epoxy composites. Varied contents of ferric ion are designed to allow comparison how the contents of formed complexes affect the surface characteristics of fiber and interfacial adhesion of composites. Compared with pure PDA modified fiber, the size and number of PDA nanospheres attached on fiber first declines distinctly and then increases as the addition level of ferric ions raises, but the coordination product of both bis-and tris-Fe3+-catechol complexes exist, only the yield of complexes varies with the addition amount of FeCl3. This indicates that the level of Fe3+ ions obviously impact DA oxidation, not the complex product. Increments in interfacial shear strength across all ferric ion-PDA complex modified fibers are noticed, associating with the stronger Fe3+…O coordination bonds that could enhance the interfacial crosslinking density. However, the optimal IFSS is attainable when appropriate amount of Fe3+ ions were added, which endows the fiber with good resin wettability. The ferric ion-PDA complex assisted surface modification demonstrated to be an effective and feasible avenue in interphase tuning of fiber reinforced composites, which could be also anticipated to extend to other metallic ion-PDA complexes.

Mixed–metal–oxide photocatalysts generated by high–temperature calcination of CaAlFe, hydrocalumite–LDHs prepared from an aluminum salt–cake

Solids with photocatalytic properties have been prepared by calcination of hydrocalumite (a sort of layered double hydroxide, LDH) at 750 °C, which had been prepared using an aluminum salt cake as a source. The characterization of the obtained solids was performed by powder X–ray diffraction, FT–infrared spectroscopy, thermal analysis, N2 adsorption–desorption isotherms at −196 °C and electron microscopy. Different crystalline phases were identified depending on the amount of Fe3+ incorporated. The Fe–free photocatalyst showed the best performance under UV light for the photodegradation of ibuprofen.

The ferroptosis in haemocytes of Pacific oyster Crassostrea gigas upon erastin treatment

Ferroptosis is an iron and oxidative dependent form of cell death usually mediated by redox related molecules in vertebrates. In the present study, a glutathione peroxidase 4 (GPX4) and a solute carrier family 7 member 11 (SLC7A11, xCT) homologues were identified from the oyster Crassostrea gigas (designed as CgGPX4 and CgxCT), which contained a GSHPx domain and an AA_permease domain, respectively. The mRNA transcripts of CgGPX4 and CgxCT were expressed in all the examined tissues, including gill, gonad, adductor muscle, labial palp, mantle, hepatopancreas and haemocytes, with the highest expression in haemocytes. After erastin treatment, the rate of cell malformation and cell death increased significantly in haemocytes, and the mitochondrial atrophy, crest loss and fracture were observed in haemocytes. While the amount of Fe2+ and Malondialdehyde (MDA) increased significantly, the mRNA expressions of CgGPX4, CgxCT and voltage-dependent anion channel 2 (CgVDAC2) in haemocytes decreased significantly after erastin treatment. These results indicated that erastin was able to induce the ferroptosis of oyster haemocytes.

Study on Fe-C-Al three-phase micro-electrolysis treatment of low concentration phosphorus wastewater

In this study, the iron-carbon-aluminum (Fe-C-Al) composite filler was prepared by aluminum modification of conventional iron-carbon (Fe-C) micro-electrolysis with a no-burn method. The optimal process conditions for Fe-C-Al three-phase micro-electrolysis treatment of low concentration phosphorus wastewater were determined to be the aluminum metal ratio of 14 wt% and solids dosing of 30 g/L. Under the optimal process conditions, Fe-C-Al three-phase micro-electrolysis was performed for the treatment of low concentration phosphorus wastewater (LCPW) with continuous experiment, while iron-carbon fillers before and after treatment were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the amount of Fe2+ dissolved in the micro-electrolysis determined the micro-electrolysis phosphorus removal effect, Al promoted the dissolution of Fe2+, and the Fe-C-Al filler had a stable phosphorus removal effect, and the average removal efficiency of phosphorus was 67.40%, which is an average improvement of 29.25% compared with the conventional Fe-C filler. The treatment of LCPW by Fe-C-Al three-phase micro-electrolysis is consistent with a first-order kinetic reaction with apparent activation energy of 38.70 kJ·mol-1, which is controlled by the chemical reaction.

Synthesis of zero-valent iron supported with graphite and plastic based carbon from recycling spent lithium ion batteries and its reaction mechanism with 4-chlorophenol in water

Graphite and plastic recycled from spent lithium ion batteries were used to synthesize zero-valent iron/graphite (ZVI/G), zero-valent iron/plastic-based carbon (ZVI/P), and zero-valent iron/graphite and plastic-based carbon (ZVI/GP) with iron oxide through carbothermic reduction. The aim of preparing these catalysts is to improve the performance of ZVI in the removal of 4-chlorophenol (4-CP) in water through heterogeneous Fenton reactions. The structural and textural properties of materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption/desorption, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The synthesis procedure successfully disperses ZVI particles on the synthesized materials. The combination of graphite and plastic-based carbon in ZVI/GP resulted in the best 4-CP removal performance. The degradation data fitted pseudo-first-order kinetic well. The Increase in the ZVI/GP dosage and the hydrogen peroxide concentration enhanced the 4-CP removal due to the increase in the amount of Fe2+ ions and reactive sites. Acidic pH increased the 4-CP removal percentage due to the high H+ concentration. The increase in the temperature favored the •OH formation and facilitated the 4-CP removal. The reaction energy of ZVI/GP reaches 53.54 kJ mol−1, which is competitive among the iron catalysts reported in literatures, and showing the 4-CP removal is reaction-controlled process. This study shows a promising way of recycling graphite and plastic in spent LIBs to prepare ZVI materials for wastewater treatment with the advantages of improved conductivity by graphite and added functional groups by plastic based carbon.

Mineralogy and Mineral Chemistry of Dioritic Dykes, Quartz Diorite Enclaves and Pyroxene of the Sungun Cu-Mo Porphyry Deposit, East Azerbaijan, Iran

The Sungun Cu-Mo porphyry deposit forms part of the Ahar–Arasbaran Magmatic Belt (AAMB). Its host Miocene porphyry stock is quartz monzonitic in composition and is cut by intermediate dykes that post-date mineralization. These dykes contain pyroxene and enclaves of ambiguous origin. Dykes of microdiorite are observed within quartz diorite dykes, whereas later diorite dykes contain three different kinds of enclaves (diorite, quartz diorite and hornfels) of sizes between 1 and 10 cm. Enclaves consist of plagioclase, hornblende and biotite, with accessory sphene, quartz and apatite. Chlorite compositions in microdiorite are within the chamosite range, whereas they are within the clinochlore range in diorite enclaves. Microprobe analyses of pyroxene indicate an augitic composition (Fs13.38-22.79Wo29.1-33.57En48.53-56.61), consistent with an igneous origin. Hornblende of the diorite enclaves formed at pressures ranging between 3 and 5.3 kilobars and temperatures between 714 and 731 °C. Average oxygen fugacity during rock formation is −14.75. Such high oxygen fugacities suggest that the diorite formed near the boundaries of a convergent margin. Amphibole compositions suggest that the diorite enclaves are sub-alkaline to mildly alkaline, consistent with reported whole-rock chemistry of the Sungun magmas. Pyroxenes were formed at pressures ranging between 11 and 15 kilobars (33–45 km) and temperatures between 1100 and 1400 °C. The amount of Fe3+ in clinopyroxene is also consistent with high oxygen fugacity within their environment of crystallization. Overall, these results have implications for our understanding of the origin of the Sungun Cu-Mo porphyry magmas and their mineral deposits in a lower-crustal setting.

Fe2(SO4)3-assisted anaerobic digestion of pig manure: the performance of biogas yield and heavy metal passivation

Abstract The harmless disposal and recycling treatment technology of livestock manure has received increasing attention in recent years. In this study, Fe2(SO4)3 was added during anaerobic digestion (AD) of pig manure (PM) to investigate the effects of different doses of Fe2(SO4)3 on biogas yield and heavy metal passivation. The results showed that the highest biogas yield was observed after adding a moderate dose of Fe2(SO4)3 (3%, based on the total solids), while the elevated result was inhibited as the Fe2(SO4)3 dosage increased. The analysis of solid digestate (solid matter remaining after AD) revealed that AD effectively passivated Cu, Zn, and As, which can be further improved with the addition of Fe2(SO4)3. However, the passivated Cd performance during this process was negligible. Furthermore, seed germination index (GI) trial results indicated that Fe2(SO4)3-assisted AD reduced the toxicity of end products to plants. To summarize, AD assisted by the addition of an appropriate amount of Fe2(SO4)3 is feasible to treat PM, and the addition of Fe2(SO4)3 at 3% was the most economic and environmental-friendly. This work could provide useful methods for the control of heavy metal pollution in the soil. Article highlights Adding 3% dose of Fe2(SO4)3 could increase methane yield by 66.76%. Fe2(SO4)3-assisted AD passivated HMs and reduced their bioavailability. The 3% Fe2(SO4)3-assisted AD significantly reduced the toxicity of end products to plants.

Induced linear and nonlinear optical modifications of nickel cadmium borosilicate glass by sunlight irradiation

Herein, we investigate the impacts of sunlight on different optical parameters of borosilicate glasses containing nickel, barium, and cadmium oxides. We studied the influence of sunlight on the optical band gap (Eg), Urbach energy (EU), refractive index (n), and nonlinear refractive index (n2) at different times of irradiations; t = 0, 40, 60, and 120 min. The absorbance of all glass samples showed a decreasing behavior, particularly in the ultraviolet (UV) range. The reduction in the UV absorption band at around 307 nm is ascribed to the photo-reduction of Fe3+ to Fe2+, producing a decrease in the amount of Fe3+ in the glass samples. The percents of changes for the studied optical parameters such as Eg, EU, n, and n2 are insignificant (<10%), confirming the glasses' stability under the effect of solar irradiation. The good stability of the investigated glasses makes them good candidates for optical applications, especially those exposed repeatedly to sunlight, such as smart windows and solar cell panels.