Inorganic Agents Research Articles

A cascade X-ray energy converting approach toward radio-afterglow cancer theranostics.

Leveraging X-rays to initiate prolonged luminescence (radio-afterglow) and stimulate radiodynamic 1O2 production from optical agents provides opportunities for diagnosis and therapy at tissue depths inaccessible to light. However, X-ray-responsive organic luminescent materials are rare due to their intrinsic low X-ray conversion efficiency. Here we report a cascade X-ray energy converting approach to develop organic radio-afterglow nanoprobes (RANPs) for cancer theranostics. RANPs comprise a radiowave absorber that down-converts X-ray energy to emit radioluminescence, which is transferred to a radiosensitizer to produce singlet oxygen (1O2). 1O2 then reacts with a radio-afterglow substrate to generate an active intermediate that simultaneously decomposes to emit radio-afterglow. Through finetuning such a cascade, intraparticle radioluminescence energy transfer and the 1O2 transfer process, RANPs possess tunable wavelengths and long half-lives, and generate radio-afterglow and 1O2 at tissue depths of up to 15 cm. Moreover, we developed a biomarker-activatable nanoprobe (tRANP) that produces a tumour-specific radio-afterglow signal, leading to ultrasensitive detection and the possibility of surgical removal of diminutive tumours (1 mm3) under an X-ray dosage 20 times lower than inorganic materials. The efficient radiodynamic 1O2 generation of tRANP permits complete tumour eradication at an X-ray dosage lower than clinical radiotherapy and a drug dosage one to two orders of magnitude lower than most existing inorganic agents, leading to prolonged survival rates with minimized radiation-related adverse effects. Thus, our work reveals a generic approach to address the lack of organic radiotheranostic materials and provides molecular design towards precision cancer radiotherapy.

Breaking New Grounds: solid-state synthesis of TiO2 – La2O3 – CuO Nanocomposites for degrading Brilliant Green dye under Visible Light

Environmental pollution, particularly from industrial dyes and chemicals, poses a significant threat to ecosystems and human health. Traditional pollution mitigation methods are often inefficient and costly. Photocatalysis has emerged as a promising solution for degrading pollutants using light energy. Titanium dioxide (TiO2) is a widely studied photocatalyst due to its stability, non-toxicity, and strong oxidative power. However, its efficiency is limited by a wide bandgap, restricting absorption to the UV region, and rapid electron-hole recombination. To address these limitations, doping TiO2 with materials like La2O3 and CuO has been explored to enhance its photocatalytic activity under visible light. This study investigates the enhancement of TiO2 nanocomposites by incorporating La2O3 and CuO. X-ray diffraction (XRD) revealed that the nanocomposites retained TiO2's anatase and rutile phases with improved crystallinity. Scanning electron microscopy (SEM) displayed spherical nanoparticles forming agglomerates, typically due to high surface energy. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of La and Cu in the TiO2 matrix. Fourier-transform infrared (FTIR) spectroscopy identified characteristic vibrational modes of Ti–O, La–O, and Cu–O bonds, suggesting strong chemical interactions between dopants and TiO2 lattice. Ultraviolet-visible (UV-Vis) spectroscopy showed a red shift in absorption spectra with La2O3 and CuO addition, reducing the bandgap energy from 3.23 eV (pure TiO2) to 2.27 eV for the TiO2–0.1La2O3–0.2CuO composite. Photoluminescence (PL) spectroscopy indicated improved charge separation and reduced electron-hole recombination rates in the synthesized nanocomposites. Photocatalytic performance was evaluated by degrading Brilliant Green (BG) dye under visible light. The TiO2–0.1La2O3–0.2CuO (TLC0.2) nanocomposite achieved a maximum dye degradation of over 95% after 204 minutes under optimal conditions (C0 = 17 mg/L and a S/L ratio of 1 g/L). Adding the inorganic agent Na2SO4 to this process significantly enhanced photocatalytic activity, increasing degradation from 56% to 95% after 180 min of visible light irradiation under C0 = 20 mg/L and S/L = 0.5 g/L conditions, as it shows a high stability after six reuse cycles. In conclusion, La2O3 and CuO doping significantly enhance TiO2 nanocomposites' crystalline structure, morphology, optical properties, and photocatalytic efficiency, demonstrating their potential for environmental remediation and solar energy conversion.

Recent Development of Organic Afterglow Probes for Diagnosis and Treatment of Cancer

Afterglow imaging plays a crucial role in the cancer treatment field. In contrast to inorganic afterglow imaging agents, organic afterglow imaging agents possess easily modifiable structures and exhibit excellent biocompatibility, thereby presenting significant prospects for application in tumor diagnosis and management. In this review, we summarize the design principles and applications of afterglow probes in tumor imaging and therapy. Finally, we discuss the future challenges and prospects of organic afterglow probes in cancer diagnosis and therapy.

Lithium-containing 45S5 Bioglass-derived glass-ceramics have antioxidant activity and induce new bone formation in a rat preclinical model of type 1 diabetes mellitus

Abstract Diabetes mellitus (DM) has been associated with complications that affect the skeletal system, such as alterations in bone repair, osteoporosis, and an increased risk of fractures. In this context, the use of biomaterials able to promote osteogenic differentiation and, at the same time, limit the oxidative stress induced by DM offers a novel perspective to ensure the repair of diabetic bone tissue. Since lithium (Li) has been recently identified as a biologically active ion with osteogenic and antioxidant properties, the localized and controlled release of Li ions from bioactive glass-ceramic materials represents a promising therapeutic alternative for the treatment of bone lesions in DM. Thus, the aim of this study was to evaluate the potential osteogenic and antioxidant effects of glass-ceramic microparticles derived from a 45S5-type bioactive glass (Bioglass) containing (% by weight) 45% SiO2, 24.5% Na2O, 24.5% CaO, and 6% P2O5, in which Na2O was partially substituted by 5% of Li2O (45S5.5Li), in an experimental model of type 1 DM (DM1). The results obtained demonstrate, for the first time, that both 45S5 and 45S5.5Li glass-ceramic microparticles possess antioxidant activity and stimulate bone formation in vivo both under physiological conditions and under experimental DM1 in rats. In this sense, they would have potential application as inorganic osteogenic agents in different strategies of bone tissue regenerative medicine.

Pyrolysis kinetic analysis of molten bioplastics based on the combination of real-time characterization and Guassian deconvolution: Case study of poly(lactic acid) materials.

Pyrolysis remains a promising method for the utilization of biogradable plastics. However, the kinetics and mechanisms of molten polymer pyrolysis are not well understood, and the effect of additives (mainly inorganic nucleating agents) on the reaction pathway has not been widely explored. In this work, we conducted a method using the thermogravimetric analysis-Fourier transform infrared spectrometry (TG-FTIR) combined with a model-fitting method, instead of a traditional method subjectively selecting a reaction model. The FTIR curves provided information for sub-reaction determination, and the detailed parameters were determined using Gaussian deconvolution. The calculation results revealed that the whole process of poly(latic acid) (PLA) pyrolysis is the random nucleation and nuclei growth model. The introduction of inorganic nucleating agents provided nuclei for PLA decomposition, decreasing the initial activation energy (E) from approximately 136 kJ·mol-1 to 88 and 79 kJ·mol-1 at a conversion rate of 0.01. However, the nucleating agent could hinder the generation of nuclei from PLA ontology, which led to the increase of E value after the nucleating agents were occupied.

Biodegradable antimicrobial films prepared in a continuous way by melt extrusion using plant extracts as effective components

Packaging plays an important role in delaying food spoilage. However, conventional packaging films do not have antimicrobial properties. Films with antimicrobial components are receiving growing research interest. However, many of the reported studies use conventional non-degradable polymers during film preparation, posing a significant threat to the environment and sustainable development. Furthermore, conventional inorganic antibacterial agents are commonly used during film preparation, posing a risk to food safety. In this study, antibacterial compounds were extracted from diverse plants, and then biodegradable antimicrobial films were prepared in a continuous way via the melt extrusion method. Especially, films prepared using Vernicia fordii and Phyllanthus urinaria extracts showed effective antibacterial activities against common foodborne pathogens. This study is the first to prepare antibacterial films in a continuous way using natural plant extracts as the effective components, and may shed new light on future research in preparing green antibacterial films via environment-friendly approaches.

In Situ Growth of Highly Compatible Cu2O-GO Hybrids Via Amino-Modification for Melt-Spun Efficient Antibacterial Polyamide 6 Fibers.

Polyamide 6 (PA6) fiber has the advantages of high strength and good wear resistance. However, it is still challenging to effectively load inorganic antibacterial agents into polymer substrates without antimicrobial activity. In this work, graphene oxide is used as a carrier, which is modified with an aminosilane coupling agent (AEAPTMS) to enhance the compatibility and antimicrobial properties of the inorganic material, as well as to improve its thermal stability in a high-temperature melting environment. Cuprous oxide-loaded aminated grapheme (Cu2O-GO-NH2) is constructed by in situ growth method, and further PA6/Cu2O-GO-NH2 fibers are prepared by in situ polymerization. The composite fiber has excellent washing resistance. After 50 times of washing, its bactericidal rates against Bacillus subtilis and Escherichia coli are 98.85% and 99.99%, respectively. In addition, the enhanced compatibility of Cu2O-GO-NH2 with the PA6 matrix improves the orientation and crystallinity of the composite fibers. Compared with PA6/Cu2O-GO fibers, the fracture strength of PA6/Cu2O-GO-NH2 fibers increases from 3.0 to 4.2 cN/dtex when the addition of Cu2O-GO-NH2 is 0.2wt%. Chemical modification and in situ concepts help to improve the compatibility of inorganic antimicrobial agents with organic polymers, which can be applied to the development of medical textiles.

Calcium Ion-Coupled Polyphosphates with Different Degrees of Polymerization for Bleeding Control.

The development of efficient hemostatic materials is crucial for achieving rapid hemorrhage control and effective wound healing. Inorganic polyphosphate (polyP) is recognized as an effective modulator of the blood coagulation process. However, the specific effect of polyP chain length on coagulation is not yet fully understood. Furthermore, calcium ions (Ca2+) are essential for the coagulation process, promoting multiple enzyme-catalyzed reactions within the coagulation cascade. Hence, calcium ion-coupled polyphosphate powders with three different degrees of polymerization (CaPP-n, n = 20, 50, and 1500) are synthesized by an ion-exchange reaction. CaPP exhibits a crystalline phase at a low polymerization degree and transitions to an amorphous phase as the polymerization degree increases. Notably, the addition of Ca2+ enhances the wettability of polyP, and CaPP promotes hemostasis, with varying degrees of effectiveness related to chain length. CaPP-50 exhibits the most promising hemostatic performance, with the lowest blood clotting index (BCI, 12.1 ± 0.7%) and the shortest clotting time (302.0 ± 10.5 s). By combining Ca2+ with polyP of medium-chain length, CaPP-50 demonstrates an enhanced ability to accelerate the adhesion and activation of blood cells, initiate the intrinsic coagulation cascade, and form a stable blood clot, outperforming both CaPP-20 and CaPP-1500. The hemostatic efficacy of CaPP-50 is further validated using rat liver bleeding and femoral artery puncture models. CaPP-50 is proven to possess hemostatic properties comparable to those of commercial calcium-based zeolite hemostatic powder and superior to kaolin. In addition, CaPP-50 exhibits excellent biocompatibility and long-term storage stability. These results suggest that CaPP-50 has significant clinical and commercial potential as an active inorganic hemostatic agent for rapid control of bleeding.

All organic nanomedicine for PDT–PTT combination therapy of cancer cells in hypoxia

Photodynamic and photothermal therapies are promising treatments for cancer, dermatological, and ophthalmological conditions. However, photodynamic therapy (PDT) is less effective in oxygen-deficient tumor environments. Combining PDT with photothermal therapy (PTT) can enhance oxygen supply and treatment efficacy. Inorganic PTT agents pose toxicity risks, limiting their clinical use despite their high performance. In this study, we developed a novel nanomedicine integrating an all-organic photothermal agent and an organic photosensitizer, creating a colocalized nanoplatform to enhance phototherapy efficacy in cancer treatment. PTT nanoparticles (NPs) were synthesized through a thermal phase transition of organic chromophores, demonstrating superior photothermal properties and photostability. Utilizing this nanoplatform, we devised ‘Combi NPs’ for combined PDT–PTT nanomedicine. Tests on A549 cancer cell lines have revealed that Combi NPs exhibit superior cytotoxicity and induce apoptosis in hypoxic conditions, outperforming PTT-only NPs. The all-organic Combi NPs show significant potential for clinical cancer phototherapy in hypoxic microenvironments, potentially mitigating long-term nanomedicine accumulation and associated toxicity.

Optimization of silty soil solidification agent ratio and mechanism of strength change based on design-expert

ABSTRACT In order to achieve the resource utilization of silty soil, based on the solidification mechanism of existing inorganic solidification agents, coal gangue and fly ash were selected as substrates, and quicklime and sodium silicate were used as activators to study a new type of muddy soil solidification agent. This project adopts mixture experimental design and unconfined compressive strength testing methods, and uses design expert software to analyze each component to obtain independent variable relationship strength prediction formulas. By using scanning electron microscope, Particles (Pores) and Cracks Analysis System, the changes in micro pore structure characteristics of Reinforced soil were obtained. The research results indicate that the relationship between the influence of various variable factors on strength gain is as follows: sodium silicate>calcium oxide>fly ash>coal gangue. As the age increases, the porosity shows a trend of first increasing and then decreasing. It has been revealed that the strength growth of Reinforced soil with curing agents is mainly due to the compaction and filling effects of hydrated calcium silicate, hydrated calcium aluminate, and a small amount of ettringite. This study is expected to provide reference for the solidification of high moisture content muddy soil.

Enhanced Crystallization of Sustainable Polylactic Acid Composites Incorporating Recycled Industrial Cement.

Globally, the demand for single-use plastics has increased due to the rising demand for food delivery and household goods. This has led to environmental challenges caused by indiscriminate dumping and disposal. To address this issue, non-degradable plastics are being replaced with biodegradable alternatives. Polylactic acid (PLA) is a type of biodegradable plastic that has excellent mechanical properties. However, its applications are limited due to its low crystallinity and brittleness. Studies have been conducted to combat these limitations using carbon or inorganic nucleating agents. In this study, waste cement and PLA were mixed to investigate the effect of the hybrid inorganic nucleating agent on the crystallinity and mechanical properties of PLA. Waste cement accelerated the lamellar growth of PLA and improved its crystallinity. The results indicate that the flexural and impact strengths increased by approximately 3.63% and 76.18%, respectively.

The Synthesis of Y-zeolite-modified CaCO3-ZnO Nanocomposites as an Antibacterial Agent

The ability of inorganic antibacterial agents like metal oxides and nanoscale inorganic materials to inhibit bacterial growth rates has yet to receive much research attention. In this study, CaCO3-ZnO/Y-zeolite nanocomposites were created utilizing coprecipitation and impregnation techniques with Ca(CH3COO)2, Zn(CH3COO)2 2H2O, Y-zeolite precursors. Physical and chemical characteristics of nanocomposites have been investigated using XRD, FTIR, and SEM-EDX characterizations. The agar-well diffusion method tested the substance for antibacterial activity against gram-positive and gram-negative bacteria. Nanocomposites have a crystal size range of 35.46-36.53 nm and a crystallinity of 35-37 %, according to the results of XRD analysis. The carbonate groups are visible in FTIR data at wave numbers 1433, 875, and 712 cm-1. The Zn-O absorption band was verified at wave numbers 600-400 cm-1. The Y-zeolite absorption bands at wave numbers 1012-997 cm-1 and 745-746 cm-1 were confirmed. The particle morphology is cube-shaped with irregular sizes. The EDX result showed that the composition consists of 35.92 % calcium, 1.68 % zinc, 44.81 % oxygen, and 13.79 % carbon as elements. With the addition of 2.5 % Y-zeolite, the antibacterial activity of nanocomposites showed the best results, with an inhibition zone diameter of 7.62 mm against Escherichia coli and 6.56 mm against Staphylococcus aureus bacteria.

Comparative study on the effect of crystalline agents for improving frost resistance of concrete from the perspective of reaction mechanism

The crystalline agents can be used to improve the concrete frost resistance by its densification effect on the microstructure of concrete, while the effect of which depends on the type and penetration process of the crystalline agents. This study, therefore, aimed to investigate the effect of two types of crystalline materials, in terms of organic and inorganic one, and two kinds of penetration methods including surface coating and soaking, in concrete. In addition to freeze-thaw test and electric flux test, the thermal gravity analysis, mercury intrusion porosimetry and scanning electron microscope were carried out. The results showed that after vacuum drying and soaking treatment, the material’s penetration depth has reached 7 mm. Deeper penetration depth shifted the freeze-thaw failure mode sudden to gradual, significantly enhancing frost resistance as a result. Among them, organic crystalline agent increased frost resistance by 2.5 times and decreased electrical flux by approximately 90 %, while inorganic crystalline agent only enhanced frost resistance by 1.5 times and reduced electrical flux by only about 37 %. From a reaction mechanism perspective, the hydrophobic layer within the pores formed by organic crystalline material has the most contribution, in which the needle-like substances generated by inorganic one filled the pores with limited effect to barrier water.

Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad.

Polyurethane polishing pads are important in chemical mechanical polishing (CMP). Thus, understanding how to decrease the density but increase the porosity is a crucial aspect of improving the efficiency of a polyurethane polishing pad. According to the principle of gas generation by thermal decomposition of sodium bicarbonate and ammonium bicarbonate, polyurethane polishing pad was prepared by a secondary foaming method. The influence of adding such an inorganic foaming agent as an auxiliary foaming agent on the structure, physical properties, and mechanical properties of polyurethane polishing pads was discussed. The results showed that compared with the polyurethane polishing pad without an inorganic foaming agent, the open-pore structure increased, the density decreased, and the porosity and water absorption increased significantly. The highest porosity and material removal rate (MRR) with sodium bicarbonate added was 3.3% higher than those without sodium bicarbonate and 33.8% higher than those without sodium bicarbonate. In addition, the highest porosity and MRR with ammonium bicarbonate were 7.2% higher and 47.8% higher than those without ammonium bicarbonate. Therefore, it was finally concluded that the optimum amount of sodium bicarbonate to be added was 3 wt%, and the optimum amount of ammonium bicarbonate to be added was 1 wt%.

Photoresponsive silver nanowire nanoplatform for real-time drug delivery in non-small cell lung cancer therapy

In this study, we first successfully synthesized three different sizes and shapes of Ag nanowires (Ag NWs) using a polyol synthesis method. The size and morphology of the Ag NWs were controlled by the types of inorganic control agents in the reaction system (NaCl for 1, CuCl2 for 2, and FeCl3 for 3). The synthesized Ag NWs were characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) experiments. Subsequently, due to the favorable width of 1, we utilized it as an effective photosensitizer to construct a novel drug-loaded nanomaterial platform, namely 1-PLC@DOX (PLC stands for poly(ε-caprolactone), and DOX stands for Doxorubicin), to achieve on-demand drug release triggered by near-infrared (NIR) laser. The results indicate that the drug delivery system can achieve minimally invasive treatment of complex geometric defects. Under near-infrared irradiation, 1-PLC@DOX can heat up to 53.6 °C within 15 min, showing a unique heating platform on the heating curve, with ideal photothermal stability and heating effect compared to other groups. By toggling near-infrared irradiation on or off, 1-PLC@DOX can exhibit a stair-step drug release curve, suggesting that on-demand control of drug release using near-infrared laser as a trigger is feasible. In vitro biological evaluations demonstrate that 1-PLC@DOX exhibits good biocompatibility and anti-tumor ability, significantly reducing the invasive ability of A549 cells on non-small cell lung cancer (NSCLC) cells, and at the same time inhibiting the proliferation of cancer cells by regulating the p53 signaling pathway to cause apoptosis.

Insight into the mechanisms of combined toxicity of cadmium and flotation agents in luminescent bacteria: Role of micro/nano particles

Currently, risk assessment and pollution management in mines primarily focus on toxic metals, with the flotation agents being overlooked. However, the combined effects of metals and flotation agents in mines remain largely unknown. Therefore, this study aimed to evaluate the combined effects of Cd and two organic flotation agents (ethyl xanthate (EX) and diethyldithiocarbamate (DDTC)), and the associated mechanisms. The results showed that Cd + EX and Cd + DDTC exhibited synergistic toxicity. The EC50 values for luminescent bacteria were 1.6 mg/L and 1.0 mg/L at toxicity unit ratios of 0.3 and 1, respectively. The synergistic effects were closely related with the formation of Cd(EX)2 and Cd(DDTC)2 micro/nano particles, with nano-particles exhibiting higher toxicity. We observed severe cell membrane damage and cell shrinkage of the luminescent bacteria, which were probably caused by secondary harm to cells through the released CS2 during their decomposition inside cells. In addition, these particles induced toxicity by altering cellular levels of biochemical markers and the transcriptional levels of transport proteins and lipoproteins, leading to cell membrane impairment and DNA damage. This study has demonstrated that particulates formed by Cd and flotation agents contribute to the majority of the toxicity of the binary mixture. This study helps to better understand the complex ecological risk of inorganic metals and organic flotation agents in realistic mining environments.

Edaphological Description of the Type Habitat of Coptis' Teeta Wall. - an Endangered Species of Medicinal Importance in Arunachal Pradesh

The edaphic conditions of the habitat of Coptis tetla Wall. have been discussed. The soils, where this species grows either under cultivation or in wild are moderately acidic to highly acidic, poor in surface porosity, very rich in silica content and possess insufficient amount of inorganic binding agents. However, the soils in cultivated fields are satisfactory in organic carbon status, water-holding ability and cation exchange capacity but inadequate presence of liming material and temperate climate adversely effect their energy materials. The 3oils at Malenja where this species is growing wild have textural limitation and anthropogenic interference. In the end the paper is concluded with suggestions. Results depict that the reasons for rarity and depletion of this species are not only anthropogenic but also environmental.

Assessing the bioaccumulation and translocation potential of vetiver grass for dioxins phytoremediation in Bien Hoa airbase, Viet Nam

Dioxins (PCDD/Fs) are well-known toxic organic pollutants that accumulate in the environment and the food chain, imposing a risk to human health and the ecosystem. Due to the use of dioxin-contaminated herbicides during the US-Vietnam War, there are several hotspots in Vietnam with very high levels of dioxins. Phytoremediation has been increasingly developed in recent decades because of its low cost and environmental-friendly aspect. Vetiver grass is a plant that can remediate both organic and inorganic agents. In this study, the uptake and translocation of dioxins in Vetiver grass (Chrysopogon zizanioides) from the dioxin-contaminated soil was investigated in a field experiment on the Bien Hoa airbase, Vietnam. An experimental area was divided into six plots, of which three were planted with Vetiver grass and three served as control plots, with the initial dioxin concentrations as following: FC2>FC3>FC1>FT2>FT3>FT1. Vetiver grass had grown well on the dioxin-contaminated soils, yielding high biomass and the level of dioxins in the roots of vetiver grass was positively correlated (r2 = 0.67; p<0.01) with its growth rate. During the first year of cultivation, Vetiver grass had the greatest capacity to efficiently accumulate dioxin. Accumulation occurs in the roots, with BAF>1 throughout the entire experiment period for FT3, and in the first year for FT1 and FT2. The dioxin translocation from the roots to the shoots was significantly lower than the BAF and less than one (TF<1), with the first and second sampling times having the highest values compared to the others. Dioxin concentrations do not provide a reliable indicator of its bioavailability but numerous other factors, such as physicochemical properties of the soil and microbes. Our study aims to contribute significant insights to capability of Vetiver grass to accumulate and translocate dioxins, hence the arsenal of dioxin remediation. Furthermore, we envisage translating our findings into practical applications in other areas, considering optimized planting techniques, growth conditions, and long-term sustainability.

Study on improving the crack self-healing width and depth based on microbial mineralization modified by Ca–Al bimetallic hydroxides

In-depth research was conducted on the application of an inorganic mineral composite microbiological remediation agent in mortar specimens with varying crack widths. Firstly, the remediation agent's efficacy in repairing cracks was validated through surface observations and macroscopic performance tests, including methods such as crack surface image capture, crack water permeability recovery rate testing, and crack ultrasonic velocity recovery testing. Subsequently, this study investigated whether the inorganic mineral and microbiological components in the remediation agent played a role by examining the repair products within the cracks. Material composition was identified using techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR). The primary minerals identified were layered double hydroxides and calcium carbonate. Furthermore, it was found that CI− and SO42− ions were immobilized within the interlayers of layered double hydroxides, aligning with the expected objectives of the experiment, thus confirming the feasibility of this study. Finally, the self-healing mechanism of cracks in this experiment was elucidated through a schematic diagram, demonstrating that the use of layered double hydroxides as inorganic minerals improved the microenvironment of the crack area, lowered the pH in the crack region, providing a favorable environment for microbial growth and mineralization. Additionally, these minerals could adsorb erosive ions such as CI− and SO42−, thereby enhancing the durability of cement-based materials.

Depletion of Free Chlorine and Generation of Trichloromethane in the Presence of pH Control Agents in Chlorinated Water at pH 6.5

Chlorine is commonly used by the fresh produce industry to sanitize water and minimize pathogen cross-contamination during handling. The pH of chlorinated water is often reduced to values of pH 6–7, most commonly with citric acid to stabilize the active antimicrobial, hypochlorous acid (a form of free chlorine). Previous studies have demonstrated that citric acid reacts with chlorine to form trichloromethane, a major chlorine by−product in water and a potential human carcinogen. However, it is unclear if other pH control agents could be used in the place of citric acid to minimize the formation of trichloromethane. The objective of the present study was to determine the reactivity of organic and inorganic pH control agents, with chlorine, to generate trichloromethane. Free chlorine (∼100 mg/L) was mixed with 10 mM of each of twelve organic acids and two inorganic pH control agents (i.e., sodium acid sulfate and phosphoric acid) to effect a pH level of 6.5. Free chlorine and trichloromethane levels were measured over 3 h at 3 and 22°C. Results demonstrated that ascorbic acid, dehydroascorbic acid, citric acid, and malic acid rapidly depleted free chlorine concentrations at both 22°C and 3°C, while tartaric acid and lactic acid decreased chlorine concentrations more slowly. Other pH control agents did not significantly reduce free chlorine either at 22 or 3°C. Citric acid led to the generation of significantly higher concentrations of trichloromethane than did other acids. Chloroacetone was also found in chlorinated water in the presence of citric acid and ascorbic acid. Taking buffering capacity and pKa values into account, phosphoric acid and some organic acids may be used to replace citric acid as pH control agents in chlorinated water for washing fresh produce, to stabilize free chlorine level and reduce the generation of trichloromethane.