Addition Of HA Research Articles

Insight into efficient degradation of pentacyclic and hexacyclic sulfonamide antibiotics by synthetic trivalent copper: Performance and mechanism

High valent metal species, including Mn(III), Fe(IV) and Cu(III), have been identified as key intermediates in the degradation of pollutants in many advanced oxidation processes. However, unlike Mn(III) and Fe(IV), the current exploration of the reaction activity and selective oxidation mechanism of Cu(III) towards pollutants with different structures is still quite limited. Herein, the copper(III) periodate was synthesized to investigate the reactivity towards six sulfonamide antibiotics (SAs) including typical two pentacyclic structures (sulfamethoxazole (SMX) and sulfathiazole (STZ)) and four hexacyclic structures (sulfadiazine (SDZ), sulfamerazine (SMR), sulfamonomethoxine (SMM) and sulfapyridine (SPD)). The results indicated that all SAs almost completely removed by Cu(III) system after 10 min with the molar ratio of approximately 3:1 (Cu(III):SAs) and Cu(III) direct oxidation played the most important role. SAs with 6-ring substituents were more readily degraded by Cu(III) than SAs with 5-ring substituents, and the presence of electron-rich group such as -CH3 and -S in ring substituent increased the reactivity towards Cu(III). The introduction of coexisting anions (Cl−, SO42− and HCO3−) hardly affected the degradation of SAs by Cu(III) oxidation, while the addition of HA to some extent inhibited SAs degradation. The solution pH greatly affected the degradation of SAs by Cu(III) and the removal efficiencies of SAs roughly followed the rule of neutral > acidic > alkaline. The degradation mechanism of SAs with 5-ring and 6-ring substituents in Cu(III) system mainly included amino nitration, self-coupling, hydroxylation, S-N cleavage in SAs with 5-ring substituents and SO2 extrusion in SAs with 6-ring substituents. Although the real water matrix inhibited the degradation of SAs to varying degrees, Cu(III) still played a satisfactory performance on SAs degradation especially for electron-rich structure.

Hydroxylamine hydrochloride-driven activation of NiFe2O4 for the degradation of phenol via peroxymonosulfate

In this study, hydroxylamine hydrochloride (HA) was employed to enhance the activation of NiFe2O4 towards peroxymonosulfate (PMS) for the effective degradation of phenol. NiFe2O4 particles were synthesized via a simple hydrothermal method, followed by characterization of their surface morphology, and microstructure. Upon the addition of HA to the system of NiFe2O4/PMS, the degradation activity is significantly enhanced. The degradation efficiency of phenol reached 98.5% after 60 min using 0.6 g/L NiFe2O4, 3 mmol/L PMS, 2 mmol/L HA at pH 7, which increased by 4.76 times compared to the system without HA. The study further explored the activation mechanism of the NiFe2O4/HA/PMS system, revealing that HA significantly enhanced the conversion of Fe3+/Fe2+ and the leaching of metal ions, thereby accelerating the reaction rate. In addition, the NiFe2O4/HA/PMS system proved effective across a broad range of pH values. This study provides new insights and perspectives into enhancing peroxymonosulfate activation coupled with metal oxides catalysts through the use of reducing agents.

Effect of Humic Amendment on Selected Hydrophysical Properties of Sandy and Clayey Soils

In recent years, products containing humic acids have been increasingly used in agriculture to improve soil parameters. Quantifying their impact on soil quality is, therefore, of key importance. This study seeks to evaluate the impact of the commercial humic acid product (HA) on the hydrophysical parameters of sandy and clayey soils sampled from different sites in Slovakia. Specifically, the study hypothesizes that humic amendment will enhance particle density (ρs), dry bulk density (ρd), porosity (Φ), saturated hydraulic conductivity (Ks), soil water repellency (SWR), and water retention capacity in sandy and clayey soils. The results of the laboratory measurements were analyzed using NCSS statistical software at a statistical significance of p < 0.05. In sandy soil, there was a statistically significant decrease in ρd and Ks and an increase in Φ and a contact angle (CA) after the application of 1 g/100 cm3 HA. At a dose of 6 g/100 cm3 HA, the values of ρs, ρd, and Ks decreased, and the Φ and CA values increased. In clayey soil, the Ks value significantly decreased by −35.5% only after the application of 6 g/100 cm3 HA. The addition of HA increased the full water capacity (FWC) and available water capacity (AWC) of clayey and sandy soils. The positive influence of HA on the studied soil parameters was experimentally confirmed, which can be beneficial, especially for their use in agricultural production.

Alleviating binary toxicity of polystyrene nanoplastics and atrazine to Chlorella vulgaris through humic acid interaction: Long-term toxicity using environmentally relevant concentrations

In this study, microalgae Chlorella vulgaris (C. vulgaris) were simultaneously exposed to environmental concentrations of amino-functionalized polystyrene nanoplastics (PS-NH2; 0.05, 0.1, 0.2, 0.3 and 0.4 mg/L) and the world's second most used pesticide, the herbicide atrazine (ATZ; 10 μg/L), in the absence and presence of humic acid (HA; 1 mg/L) for 21 days. Due to the low concentrations of PS-NH2, the majority of them could not cause a significant difference in the end-points of biomass, chlorophylls a and b, total antioxidant, total protein, and superoxide dismutase and malondialdehyde compared to the control group (p > 0.05). On the other hand, by adding ATZ to the PS-NH2, all the mentioned end-point values showed a considerable difference from the control (p < 0.05). The exposure of PS-NH2+ATZ treatments to the HA could remarkably reduce their toxicity, additionally, HA was able to decrease the changes in the expression of genes related to oxidative stress (e.g., superoxide dismutase, glutathione reductase, and catalase) in the C. vulgaris in the most toxic treatment group (e.g., PS-NH2+ATZ). The synergistic toxicity of the PS-NH2+ATZ group could be due to their enhanced bioavailability for algal cells. Nevertheless, the toxicity alleviation in the PS-NH2+ATZ treatment group after the addition of HA could be due to the eco-corona formation, and changes in their zeta potential from positive to negative value, which would increase their electrostatic repulsion with the C. vulgaris cells, in such a way that HA also caused a decrease in the formation of C. vulgaris-NPs hetero-aggregates. This research underscores the complex interplay between PS-NH2, ATZ, and HA in aquatic environments and their collective impact on microalgal communities.

Nutrient controlled release behaviors and plant growth of NPK encapsulated hydroxyapatite/alginate biocomposite toward agricultural and environmental sustainability

Abstract Controlled release fertilizers (CRFs) promote sustainable agriculture by gradually releasing nutrients into the soil while also mitigating environmental pollution. Nitrogen-phosphorus-potassium embedded hydroxyapatite/alginate (NPK-HA/Alg) biocomposite beads were developed using a simple, cost-effective, and environmentally friendly dropping and external gelation method. Addition of eggshell biowaste-derived HA to the alginate matrix improved the structural, thermal, and structural stability of the alginate beads, and enabled the inclusion of significantly high plant nutrients. The biocomposite beads exhibited a prolonged and controlled nutrient release in deionized water over 35 days. Biocomposite bead addition was assessed for the growth of flowering Chinese cabbage in a controlled greenhouse environment. Results confirmed vegetative growth with high values of plant height, number of leaves, and fresh and dry weights. The non-toxic and cost-effective NPK-HA/Alg biocomposite beads demonstrated controlled nutrient release as promising CRF materials to promote sustainable agricultural production.

Hydroxylamine-assisted retarding surface passive layer of zero-valent iron for highly efficient p-nitrophenol removal via direct electron transfer

Zerovalent iron (ZVI) has been widely used in groundwater remediation due to its excellent reducibility. However, the passivation layer on ZVI surface limits the reactivity of ZVI. In this work, hydroxylamine hydrochloride (HA) has been selected to assist to improve the remediation efficiency of ZVI, and the removal rate constant of p-nitrophenol (PNP) increased nearly 90 times than that of ZVI alone. The effect of HA concentration on the degradation efficiency of PNP by ZVI was also discussed. The concentrations of Fe(Ⅱ) and Fe(Ⅲ) in reaction solution and on ZVI surface during the processes were measured. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) of fresh and used ZVI were characterized, which elucidated that HA could facilitate the reduction of Fe(Ⅲ) to Fe(Ⅱ), retard passivation, and extend the pH range of reaction. The mechanism of high degradation efficient in ZVI/HA system was studied through a series of probing experiments. Fe0 directly donated electron to reduce PNP, which was the fundamental reason. The contribution of Fe(Ⅱ) and active hydrogen generated on ZVI surface to the degradation efficiency of PNP could be negligible. It can be concluded that the addition of HA was an effective strategy to improve the reduction efficiency of ZVI.

Synthesis of Cu Nanoparticles Incorporated Mesoporous C/SiO2 for Efficient Tetracycline Degradation.

In this study, a Cu NPs-incorporated carbon-containing mesoporous SiO2 (Cu/C-SiO2) was successfully synthesized through a grinding-assisted self-infiltration method followed by an in situ reduction process. The obtained Cu/C-SiO2 was then employed as a Fenton-like catalyst to remove tetracycline (TC) from aqueous solutions. TEM, EDS, XRD, N2 adsorption-desorption, FTIR, and XPS methods were used to characterize the crystal structure, morphology, porosity, chemical composition, and surface chemical properties of the catalyst. The effects of initial TC concentration, catalyst dosage, H2O2 dosage, solution pH, HA addition, and water media on the TC degradation over Cu/C-SiO2 were investigated. Scavenging and electrochemical experiments were then carried out to analyze the TC degradation mechanism. The results show that the Cu/C-SiO2 can remove 99.9% of the concentrated TC solution (C0 = 500 mg·L-1), and it can be used in a wide pH range (R.E. = 94-99%, pH = 3.0-11.0). Moreover, hydroxyl radicals (•OH) were detected to be the dominant reactive species in this catalytic system. This study provides a simple and promising method for the synthesis of heteroatom-containing mesoporous catalysts for the decomposition of antibiotics in wastewater.

Reducing agents enhanced prometon degradation by CuBi2O4/peroxymonosulfate: Development of interfacial electron transport and circulation of Cu+/Cu2+

Herein, hydroxylamine hydrochloride (HA) or ascorbic acid (AA) was utilized to develop the performance of CuBi2O4 activating peroxymonosulfate (PMS) for degradation prometon (PMT), which was effective for the advanced treatment of pesticide wastewater, based on which the reaction mechanism of reducing agents enhanced solid-activated PMS was discussed in the points of electron transfer and the circulation of Cu+/Cu2+. The enhanced electron transfer mechanism of promoting Cu(I)/Cu(II) cycle was confirmed firstly by electrochemical characterization and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the kinetic model results showed that the generation rate of SO4•− increase by 1.8 times and 2.9 times with the addition of AA or HA, respectively. AA was the quenching agent of •OH due to the stronger reactive with •OH and showed a lower enhancing efficiency. The transformation intermediates of PMT also supported the different derived reactive radicals, based on Density Functional Theory calculation. More importantly, the intermediates of HA and AA were also identified as the first report, based on which their application sense was sited. The work provided a novel and safe insight for improving PMS activation by solid catalysts using HA and AA.

Electroactive membrane with the electroactive layer beneath the separation layer to eliminate the interference of humic acid in the oxidation of antibiotics

Removing harmful antibiotics is essential to reclaiming water from municipal secondary effluent. Electroactive membranes are effective in the removal of antibiotics but challenged by the abundant coexisting macromolecular organic pollutants in municipal secondary effluent. To eliminate the interference of macromolecular organic pollutants in the removal of antibiotics, we propose a novel electroactive membrane with a top polyacrylonitrile (PAN) ultrafiltration layer and a bottom electroactive layer composed of carbon nanotubes (CNTs) and polyaniline (PANi). When filtering the mixture of tetracycline (TC, a typical antibiotic) and humic acid (HA, a typical macromolecular organic pollutant), the PAN-CNT/PANi membrane performed sequential removal. It retained HA at the PAN layer (by ∼96%) and allowed TC to reach the electroactive layer where it was electrochemically oxidized (e.g., by ∼92% at 1.5 V). The TC removal of the PAN-CNT/PANi membrane was marginally affected by HA, unlike that of the control membrane with the electroactive layer on the top that showed decreased TC removal after the addition of HA (e.g., decreased by 13.2% at 1 V). The decreased TC removal of the control membrane was attributed to the attachment (but not competitive oxidation) of HA on the electroactive layer that impaired the electrochemical reactivity. The HA removal prior to TC degradation realized by the PAN-CNT/PANi membrane avoided the attachment of HA and guaranteed TC removal on the electroactive layer. Long-term filtration for 9 h revealed the stability of the PAN-CNT/PANi membrane, and its advantageous structural design was conformed in the context of real secondary effluents.

Boron nitride nanofiber/Zn-doped hydroxyapatite/polycaprolactone scaffolds for bone tissue engineering applications.

In this study, Zn doped hydroxyapatite (Zn HA)/boron nitride nanofiber (BNNF)/poly-ε-caprolactone (PCL) composite aligned fibrous scaffolds are produced with rotary jet spinning (RJS) for bone tissue engineering applications. It is hypothesized that addition of Zn HA and BNNF will contribute to cell viability as well as mechanical and osteogenic properties of the PCL scaffolds. Zn HA was synthesized by mixing Ca and P sources followed by sonication and aging whereas BNNF was obtained by the reaction of melamine with boric acid followed by freeze-drying for annealing of fibers. It is found that incorporation of both Zn HA and BNNF in PCL fibers resulted in higher calcium phosphate (CaP) precipitation on the scaffolds. Also, in vitro cell culture studies showed that presence of both Zn HA and BNNF also had synergistic effect for enhanced proliferation and osteogenic activity of Saos-2 cells. Mechanical properties of PCL-Zn HA-BNNF were found similar to that of non-load bearing bones. Furthermore, the presence of Zn HA and BNNF had synergistic effects to cell attachment, proliferation and spreading without causing cytotoxic effect on cells. The highest ALP activity was obtained in the PCL-Zn HA- BNNF group at days 7 and 14 due to release of zinc, calcium, phosphate and boron. Considering its mechanical and bioactivity properties, PCL-Zn HA-BNNF composite scaffolds hold promise as non-load bearing bone substitutes.

Modified green waste compost as growing substrates on the effective components of medicinal plants perilla (Perilla frutescens (L.) Britt.) and mint (Mentha haplocalyx Briq.)

Soilless substrates supporting plant production have been the research focus in recent decades. Green waste compost (GWC)-based substrates have shown the feasibility in improving plant production, but the research of GWC as growing substrate to improve the quality of medicinal plants was limited. The objective of this study was to explore the effects of GWC substrates modified by matured peanut shell (MPS, at 0, 10, 20 %; by vol.) and humic acid (HA, at 0, 3, 6 %; by weigh.) on the effective components of medicinal plants perilla (Perilla frutescens (L.) Britt.) and mint (Mentha haplocalyx Briq.). The 100% GWC substrates was used as control. The hydrologic-physical and biochemical properties of growing substrates and the biomass accumulation, secondary metabolite synthesis, essential oil production, and chemical composition of both herbs were investigated. Results showed that both perilla and mint grown in GWC substrates amended with MPS and HA had better performance than the control. The addition of additives (MPS and HA) positively affected the biomass accumulation of perilla and mint. The combination of the highest doses of MPS and HA (20 % and 6 %, respectively) resulted in an accumulation of total fresh weight and total dry weight several times (the total fresh and dry weight of perilla was 2.70 and 2.37 times, the total fresh and dry weight of mint was 1.47 and 1.51 times, respectively) greater than that of the control. Furthermore, the addition of MPS and HA could improve the secondary metabolite synthesis of mint and perilla and this synthesis was related to the hydrologic-physical and biochemical properties of growing substrates. Unexpectedly but reasonably, perilla was more sensitive to the addition of MPS while there was no significant (p < 0.05) correlation between the addition of MPS or HA for mint and the addition of HA for perilla. Notably, the best effective components of both herbs were achieved when perilla grown in GWC modified by 20 % MPS and 3 % HA and mint grown in GWC modified by 10 % MPS and 6 % HA. Overall, the quality of GWC could be effectively modified by the addition of MPS and HA and the modified GWC could be used as an environmentally and friendly substrate to improve the effective components of mint and perilla.

The role of three-dimensional scaffolds based on polyglycerol sebacate/ polycaprolactone/ gelatin in the presence of Nanohydroxyapatite in promoting chondrogenic differentiation of human adipose-derived mesenchymal stem cells

BackgroundTissue engineering for cartilage regeneration has made great advances in recent years, although there are still challenges to overcome. This study aimed to evaluate the chondrogenic differentiation of human adipose-derived mesenchymal stem cells (hADSCs) on three-dimensional scaffolds based on polyglycerol sebacate (PGS) / polycaprolactone (PCL) / gelatin(Gel) in the presence of Nanohydroxyapatite (nHA).Materials and methodsIn this study, a series of nHA-nanocomposite scaffolds were fabricated using 100:0:0, 60:40:0, and 60:20:20 weight ratios of PGS to PCL: Gel copolymers through salt leaching method. The morphology and porosity of prepared samples was characterized by SEM and EDX mapping analysis. Also, the dynamic contact angle and PBS adsorption tests are used to identify the effect of copolymerization and nanoparticles on scaffolds' hydrophilicity. The hydrolytic degradation properties were also analyzed. Furthermore, cell viability and proliferation as well as cell adhesion are evaluated to find out the biocompatibility. To determine the potential ability of nHA-nanocomposite scaffolds in chondrogenic differentiation, RT-PCR assay was performed to monitor the expression of collagen II, aggrecan, and Sox9 genes as markers of cartilage differentiation.ResultsThe nanocomposites had an elastic modulus within a range of 0.71–1.30 MPa and 0.65–0.43 MPa, in dry and wet states, respectively. The PGS/PCL sample showed a water contact angle of 72.44 ± 2.2°, while the hydrophilicity significantly improved by adding HA nanoparticles. It was found from the hydrolytic degradation study that HA incorporation can accelerate the degradation rate compared with PGS and PGS/PCL samples. Furthermore, the in vitro biocompatibility tests showed significant cell attachment, proliferation, and viability of adipose-derived mesenchymal stem cells (ADMSCs). RT-PCR also indicated a significant increase in collagen II, aggrecan and Sox9 mRNA levels.ConclusionsOur findings demonstrated that these nanocomposite scaffolds promote the differentiation of hADSCs into chondrocytes possibly by the increase in mRNA levels of collagen II, aggrecan, and Sox9 as markers of chondrogenic differentiation. In conclusion, the addition of PCL, Gelatin, and HA into PGS is a practical approach to adjust the general features of PGS to prepare a promising scaffold for cartilage tissue engineering.Graphical

Effects of high acyl gellan gum on the rheological properties, stability, and salt ion stress of sodium caseinate emulsion

Sodium caseinate (SC) is widely used as a biological macromolecular emulsifier in oil-in-water (O/W) emulsions. However, the SC-stabilized emulsions were unstable. High-acyl gellan gum (HA) is an anionic macromolecular polysaccharide that improves emulsion stability. This study aimed to investigate the effects of HA addition on the stability and rheological properties of SC-stabilized emulsions. Study results revealed that HA concentrations >0.1 % could increase Turbiscan stability, reduce the volume average particle size, and increase the zeta-potential absolute value of the SC-stabilized emulsions. In addition, HA increased the triple-phase contact angle of SC, transformed SC-stabilized emulsions into non-Newtonian fluids, and effectively inhibited the movement of emulsion droplets. The effect of 0.125 % HA concentration was the most effective, allowing SC-stabilized emulsions to maintain good kinetic stability over a 30-d period. NaCl destabilized SC-stabilized emulsions but had no significant effect on HA-SC emulsions. In summary, HA concentration had a significant effect on the stability of SC-stabilized emulsions. HA altered the rheological properties and reduced creaming and coalescence by forming a three-dimensional network structure, increasing the electrostatic repulsion of the emulsion and the adsorption capacity of SC at the oil-water interface, and thereby improving the stability of SC-stabilized emulsions during storage and in the presence of NaCl.

Preparation and Characterization of Cellulose Acetate-Hydroxyapatite (CA-HA) Composite Membrane for Ultrafiltration Process

A composite material is of two or more combined constituents with disparate properties and forming an inseparable component with novel characteristics. This study was aimed to acquire cellulose acetatehydroxyapatite (CA-HA) composite membrane and apply it in an ultrafiltration process. HA was synthesized hydrothermally from pre-calcined-eggshell calcium oxide. The CA-HA composites were prepared by addition of HA to give final HA composition of 0, 4 and 5% (w/w). The addition of HA altered CA morphologies and constricted the porous of CA-HA over the pure CA. The tensile strength analysis suggested that CA with 4% and 5% HA showed increasing tensile strength form 0.15 MPa for pure CA to 0.35 and 0.2 MPa respectively.

Microstructure, mechanical properties and fracture toughness of ECAPed magnesium matrix composite reinforced with hydroxyapatite ceramic particulates for bioabsorbable implants

Employing ceramic particles like hydroxyapatite to fabricate magnesium-based bio-composite has received incredible attention in orthopedic applications due to their bioactivity and biocompatibility. Besides, applying severe plastic deformation methods like equal channel angular pressing (ECAP), in addition to eliminating defects induced by casting, causes the metallurgical and mechanical behavior improvement of Mg/HA bio-composites. In this paper, the combined effects of HA particles and the ECAP process with Bc route on the microstructure, mechanical properties, and fracture toughness behavior of Mg/HA bio-composite fabricated through the electromagnetic and mechanical stir casting method were evaluated. Furthermore, a non-contact digital image correlation (DIC) method was adopted to accurately assess the elastic and plastic parameters and crack propagation during the fracture toughness test. Microstructural observation demonstrated that the addition of HA particles and, subsequently, applying four passes of the ECAP process on the bio-composites not only decreased the grain size by a considerable amount of 92%, but also resulted in a homogenous microstructure. Moreover, according to the results of the mechanical tests, after four-pass ECAP, although the compressive yield stress of Mg/HA bio-composite did not significantly change, the highest tensile yield stress, ultimate tensile, and compressive strength were accomplished. Among all elastic and plastic parameters, the elastic modulus and strength coefficient have continuously risen with adding HA and increasing the number of ECAP passes. However, the strain hardening exponent has decreased noticeably with the addition of HA, and the ECAP process compensated for some of this reduction. In addition, reinforcing magnesium with HA particles and improving the dislocation density caused by increasing the number of ECAP passes has led to increased material resistance against crack growth, wasted energy, and, consequently, fracture toughness. In this case, the four-pass ECAPed bio-composite showed the highest fracture toughness, approximately 28 MPa m0.5, 70% more than the pure Mg.

3D scaffolds of caprolactone/chitosan/polyvinyl alcohol/hydroxyapatite stabilized by physical bonds seeded with swine dental pulp stem cell for bone tissue engineering

Bone Regeneration represents a clinical need, related to bone defects such as congenital anomalies, trauma with bone loss, and/or some pathologies such as cysts or tumors This is why a polymeric biomaterial that mimics the osteogenic composition and structure represents a high potential to face this problem. The method of obtaining these materials was first to prepare a stabilized hydrogel by means of physical bonds and then to make use of the lyophilization technique to obtain the 3D porous scaffolds with temperature conditions of −58 °C and pressure of 1 Pa for 16 h. The physicochemical and bioactive properties of the scaffolds were studied. FTIR and TGA results confirm the presence of the initial components in the 3d matrix of the scaffold. The scaffolds exhibited a morphology with pore size and interconnectivity that promote good cell viability. Together, the cell viability and proliferation test, Alamar BlueTM and the differentiation test: alizarin staining, showed the ability of physically stabilized scaffolds to proliferate and differentiate swine dental pulp stem cell (DPSCs) followed by mineralization. Therefore, the Cs-PCL-PVA-HA scaffold stabilized by physical bonds has characteristics that suggest great utility for future complementary in vitro tests and in vivo studies on bone defects. Likewise, this biomaterial was enhanced with the addition of HA, providing a scaffold with osteoconductive properties necessary for good regeneration of bone tissue.Graphical abstract

Chromium Transport and Fate in Vadose Zone: Effects of Simulated Acid Rain and Colloidal Types.

Chromium (Cr) can enter groundwater through rainfall infiltration and significantly affects human health. However, the mechanisms by which soil colloids affect chromium transport are not well investigated. In this study, column experiments were conducted to simulate the chromium (Cr) transport mechanism in two typical soils (humic acid + cinnamon soil and montmorillonite + silt) in the vadose zone of a contaminated site and the effects of acid rain infiltration conditions. The results showed that Mt colloids have less influence on Cr. The fixation of Cr by colloid mainly occurs in the cinnamon soil layer containing HA colloid. The adsorption efficiency of Cr was increased by 12.8% with the addition of HA. In the HA-Cr system, the introduction of SO42- inhibited the adsorption of Cr, reducing the adsorption efficiency from 31.4% to 24.4%. The addition of Mt reduced the adsorption efficiency of Cr by 15%. In the Mt-Cr system, the introduction of SO42- had a promoting effect on Cr adsorption, with the adsorption efficiency increasing from 4.4% to 5.1%. Cr release was inhibited by 63.88% when HA colloid was present, but the inhibition owing to changes in acidity was only 14.47%. Mt colloid promotes Cr transport and increases the leaching rate by 2.64% compared to the absence of Mt. However, the effect of acidity change was not significant. Intermittent acid rain will pose a higher risk of pollutant release. Among the influencing factors, the type of colloid had the most significant influence on the efficiency of Cr leaching. This study guides the quantitative assessment of groundwater pollution risk caused by Cr in the vadose zone.

3D‐printing polylactic acid/hydroxyapatite fracture internal fixation plates for bone repair

AbstractFracture internal fixation plates are the most common implants in internal fixation and have been applied to fix fractures for over a hundred years. Plates of metal material remain the gold standard. However, they are not the ideal bone plate considering the stress shielding induced by the high elastic modulus and biomechanical mismatch with bone. PLA fracture internal fixation plates present the advantages of matching with the elastic modulus of the bone and absorbable properties but are limited by poor toughness and acidic degradation. Degradable bone plates composed of polylactic acid/hydroxyapatite (PLA/HA) composite were prepared by fused deposition modeling, which had higher bending strength and compressive strength than that of pure PLA. The hydrophilicity of PLA/HA composite was improved by the addition of HA, it was beneficial to the adhesion of cells on the surface of the composite. The results of in vitro degradability showed that the addition of HA can effectively neutralize the acidity generated by PLA degradation. Meanwhile, the addition of HA can improve the cell affinity to promote the adhesion and growth of MC3T3‐E1 cells on the surface of the composites. Consequently, the PLA/HA composite shows a good potential as a bone plate to fix bone fractures.

Solar light promoted degradation of bisphenol s in carbonate/peroxymonosulfate system through accelerating singlet oxygen generation

This study investigated for the first time the potential of the novel combination of peroxymonosulfate (PMS) and carbonate (CO32−) toward bisphenol S (BPS) under solar light irradiation. Compared with the Na2CO3/PMS and solar/PMS system, the solar/Na2CO3/PMS system significantly reduces the time required for the degradation of BPS. The excellent removal performance is possible due to the synergistic effect between enhanced light absorption and PMS activation, which accelerated the decomposition of PMS to generate more reactive oxygen species. Scavenging tests and electron paramagnetic resonance analysis revealed that the singlet oxygen (1O2) was the dominant oxidant formed and contributed to BPS elimination with a small proportion of superoxide anion radical (O2•–), rather than sulfate radical (SO4•−) and hydroxyl radical (HO•). The addition of Cl− could promote the degradation of BPS, but the addition of HA and a higher HCO3− concentration inhibited this process. The presence of SO42− and NO3− slightly promote the degradation of BPS. Besides, the solar/Na2CO3/PMS system represented significant degradation efficiency in a wide initial pH range (5.02–10.96). Such a system is favorable for the application in actual water matrices such as domestic wastewater, river water, lake water, and tap water. Meanwhile, based on the intermediates identified, the possible degradation pathways of BPS were proposed. In addition, most of the degradation intermediates of BPS were less toxic to different organisms than the parent compound. Moreover, the highly efficient degradation of several typical organic contaminants was also achieved using the solar/Na2CO3/PMS system under simulated and natural solar light irradiation. This study provides a novel idea and demonstrates the great potential for the elimination of organic pollutants in water.

The effect of hydroxyapatite filler on biodegradable poly(sorbitol sebacate malate) composites

AbstractBiodegradable poly(sorbitol sebacate malate)/hydroxyapatite (PSSM/HA) composites were successfully synthesized through one step catalyst‐free polycondensation of sorbitol, sebacic acid, malic acid, and HA powder as filler for the composites. The addition of HA improved the tensile modulus and strength of the materials compared with pure PSSM. The elongation at break of the composites was slightly reduced with increasing HA content. The PSSM and HA showed good compatibility, which was evidenced by good distributions of HA particles in the matrix. In vitro degradation and cytotoxicity tests were conducted to investigate the degradation profile and the toxicity of the biocomposites, respectively. The biocomposites also degraded nearly up to ~50% after 6 weeks of study and the degradation products were shown non‐cytotoxic. It was observed that the biocomposites were soft, elastic with Young's modulus and also biodegradable which is potential to be used in biomedical fields such as tissue engineering application.