This investigation examines the development of titanium slag-flue gas desulfurized gypsum-Portland cement ternary composites (the ternary composites) for the solidification and stabilization of Pb-contaminated soils. The efficacy of the ternary composites is systematically evaluated using a combination of experimental methodologies, including mechanical properties such as unconfined compressive strength, stress-strain behavior and elastic modulus, leaching toxicity, XRD, TG-DTG, FTIR, XPS, and SEM-EDS analyses. The results indicate that the mechanical properties of Portland cement solidified Pb-contaminated soils are inferior to those of Portland cement solidified Pb-free soil, both in the early and later stages. However, the mechanical properties of Pbcontaminated soils solidified by the ternary composites are superior to those of the ternary composites solidified Pb-free soils in the early stage but somewhat inferior in the later stage. The ternary composites significantly decrease the leached Pb concentrations of solidified Pb-contaminated soils, which somewhat increase with the Pb content and with the pH value decrease of the leaching agent. Moreover, with much lower carbon emissions index and strength normalized cost, the ternary composites have comparable stabilization effects on Pbcontaminated soils to Portland cement, suggesting that the ternary composites can serve as a viable alternative for the effective treatment of Pb-contaminated soils. Characterization via TG-DTG and XRD reveals that the primary hydration products of the ternary composite solidified Pb-contaminated soils include gypsum, ettringite, and calcite. Furthermore, FTIR, XPS and SEM-EDS analyses demonstrate that Pb ions are effectively adsorbed onto these hydration products and soil particles.

This study focused on synthesizing polyvinyl alcohol (PVA) utilizing glutaraldehyde (GA) as a crosslinking agent and silicon dioxide (SiO2) nanopowder with titanium dioxide (TiO2) nanopowder to reduce or prevent the hydrophilic property of PVA. Integrating SiO2 and TiO2 into the PVA boosted the hydrophobicity, thermal properties, and self-cleaning of the PVA film. The characteristic properties of PVA/GA, PVA/SiO2/GA, and PVA/SiO2/TiO2/GA nanocomposites polymer membranes were investigated by gel content, swelling capacity, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction patterns (XRD), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and contact angle. The resulting PVA/5%SiO2/1%TiO2/GA nanocomposite exhibits much better physical properties than PVA/GA hydrogel (water absorbency from 3.1 g/g to 0.07 g/g and contact angel from 0 degrees to 125 degrees). In addition, the nanocomposite retains very low swelling properties. These prepared nanocomposites are promising in a variety of applications such as sand soil stabilizers, construction, and building works where they exhibit excellent water resistance performance. This study introduces a novel approach for creating hydrophobic polymeric membranes from hydrophilic polymeric materials to stabilize sandy soil effectively.

An Integrated Process Intensification (IPI) technology-based roadmap is proposed for the utilization of renewables (water, air and biomass/unavoidable waste) in the small-scale distributed production of the following primary products: electricity, H-2, NH3, HNO3 and symbiotic advanced (SX) fertilizers with CO2 mineralization capacity to achieve negative CO2 emission. Such a production platform is an integrated intensified biorefinery (IIBR), used as an alternative to large-scale centralized production which relies on green electricity and CCUS. Hence, the capacity and availability of the renewable biomass and unavoidable waste were examined. The critical elements of the IIBR include gasification/syngas production; syngas cleaning; electricity generation; and the conversion of clean syngas (which contains H-2, CO, CH4, CO2 and N-2) to the primary products using nonthermal plasma catalytic reactors with in situ NH3 sequestration for SA fertilizers. The status of these critical elements is critically reviewed with regard to their techno-economics and suitability for industrial applications. Using novel gasifiers powered by a combination of CO2, H2O and O-2-enhanced air as the oxidant, it is possible to obtain syngas with high H-2 concentration suitable for NH3 synthesis. Gasifier performances for syngas generation and cleaning, electricity production and emissions are evaluated and compared with gasifiers at 50 kWe and 1-2 MWe scales. The catalyst and plasma catalytic reactor systems for NH3 production with or without in situ reactive sequestration are considered in detail. The performance of the catalysts in different plasma reactions is widely different. The high intensity power (HIP) processing of perovskite (barium titanate) and unary/binary spinel oxide catalysts (or their combination) performs best in several syntheses, including NH3 production, NOx from air and fertigation fertilizers from plasma-activated water. These catalysts can be represented as BaTi1-vO3-x{#}(y)N-z (black, piezoelectric barium titanate, bp-{BTO}) and (M3-jMkO4-m)-M-(1)-O-(2){#}(n)N-r/SiO2 (unary (k = 0) or a binary (k > 0) silane-coated SiO2-supported spinel oxide catalyst, denoted as M/Si = X) where {#} infers oxygen vacancy. HIP processing in air causes oxygen vacancies, nitrogen substitution, the acquisition of piezoelectric state and porosity and chemical/morphological heterogeneity, all of which make the catalysts highly active. Their morphological evaluation indicates the generation of dust particles (leading to porogenesis), 2D-nano/micro plates and structured ribbons, leading to quantum effects under plasma catalytic synthesis, including the acquisition of high-energy particles from the plasma space to prevent product dissociation as a result of electron impact. M/Si = X (X > 1/2) and bp-{BTO} catalysts generate plasma under microwave irradiation (including pulsed microwave) and hence can be used in a packed bed mode in microwave plasma reactors with plasma on and within the pores of the catalyst. Such reactors are suitable for electric-powered small-scale industrial operations. When combined with the in situ reactive separation of NH3 in the so-called Multi-Reaction Zone Reactor using NH3 sequestration agents to create SA fertilizers, the techno-economics of the plasma catalytic synthesis of fertilizers become favorable due to the elimination of product separation costs and the quality of the SA fertilizers which act as an artificial root system. The SA fertilizers provide soil fertility, biodiversity, high yield, efficient water and nutrient use and carbon sequestration through mineralization. They can prevent environmental damage and help plants and crops to adapt to the emerging harsh environmental and climate conditions through the formation of artificial rhizosphere and rhizosheath. The functions of the SA fertilizers should be taken into account when comparing the techno-economics of SA fertilizers with current fertilizers.

2021 is the first year of China's 14th Five-Year Plan and the first five years when China has embarked on a new journey to become a comprehensive and modern socialist country. Its meaning is self-evident. One of them will focus on green and low-carbon development, continue to improve environmental quality, improve the quality and stability of ecosystems, and comprehensively reform the utilization rate of resources. As a new round of transportation infrastructure construction to accelerate the further increase of building materials demand, large-scale solid waste recycling industrial production is on the agenda such as bulk solid waste, titanium slag powder not only occupies a lot of land resources, groundwater pollution, titanium slag powder in the natural environment also destroyed the environment, affect the sustainable development of economy. The so-called solidification material of titanium dioxide slag uses titanium dioxide slag, cement, curing agent, and lime as the main raw materials. After corresponding processing, a new type of titanium dioxide slag solidified soil is generated. Its mechanical properties and water resistance have reached technical requirements for pavement base application. This article focuses on the current situation of titanium dioxide slag, and in order to ensure the sustainable development of the industry, the application of road fluid new materials and their processes to improve and solidify titanium dioxide slag technology in transportation infrastructure engineering has achieved good results, truly turning waste into treasure. In view of the research results of this article, it is recommended that this technology should be promoted and applied in the future.

This study investigates the utilization of titanium gypsum (TG) and construction waste soil (CWS) for the development of sustainable, cement-free Controlled Low Strength Material (CLSM). TG, combined with ground granulated blast furnace slag, fly ash, and quicklime, serves as the binder, while CWS replaces natural sand. Testing thirteen mixtures revealed that a CWS replacement rate of over 40% controls bleeding below 5%, with a water-to-solid ratio between 0.40 and 0.46, ensuring flowability. Higher TG content reduces flowability but is crucial for strength due to its role in forming a crystalline network. Compressive strength decreases with higher TG and water-to-solid ratio, while 3-5% quicklime provides a 56 day strength below 2.1 MPa. Higher CWS reduces expansion, and TG content between 60% and 70% minimizes volume changes. XRD and SEM analyses underscore the importance of controlling TG and quicklime content to optimize CLSM's mechanical properties, highlighting the potential of TG and CWS in creating low carbon CLSM.

This study investigates an environmentally friendly bioplastic made from cornstarch with fructose and different amounts of titanium dioxide (TiO2). The research focuses on its physical, chemical bonding, and nutritional properties. X-ray diffraction analysis indicates that TiO2 influences diffraction peaks, affecting the crystal size, with the smallest size of 12.54 nm observed in Sample (II) containing 0.1 g of TiO2. Fourier transform infrared analysis shows slight shifts in the stretching of the-OH groups, indicating consistent elemental composition. The mechanical properties of the bioplastic for Sample (I) lacking TiO2 exhibits the highest Young's modulus of 1.02593 MPa and a tensile strength of 0.1345 MPa. In terms of biodegradation, the cornstarch-based bioplastic decomposes by approximately 80 % in soil after 28 days, aided by moisture and soil microorganisms. Water resistance analysis of the cornstarch-based bioplastic indicates that the sample containing 0.1 g of TiO2 exhibits the highest percentage, with 66.66 % absorption after 120 s. Nutrient concentration analysis using mung bean plants shows increased levels of calcium, potassium, and iron in samples with TiO2, particularly in Sample (II) containing 0.1 g of TiO2, which has significantly higher nutrient content, namely 2.15 % calcium, 1.99 % potassium, and 424.46 ppm iron.

Dealing with collapsible soils consistently presents a crucial challenge for geological and geotechnical engineers. Loess soil is among the most widely recognized types of collapsible soils, covering approximately 10 % of the Earth's land surface. Loessic soil is a sedimentary deposit primarily composed of silt-size grains, loosely bound together by calcium carbonate. In Iran, approximately 17 % of Golestan province is covered by silty, clayey, and sandy loesses, primarily composed of loessic soil. Additionally, several energy transmission lines in this province traverse these loess-covered areas. Based on the reports from Golestan Gas Company experts, the scouring of gas pipeline channels in various regions, such as Dashli-Alum in Maraveh-Tappeh city, causes significant risks in the traffic roads and is one of the most critical issues facing this company. This research assessed the dispersion and collapse potentials of loess soil using a range of field exploration and laboratory testing methods. These methods included atomic absorption spectroscopy, the double hydrometer, scanning electron microscope photography, wavelength-dispersive X-ray fluorescence spectrometry, and consolidation tests. The results indicate that soil collapsibility was acquired as one of the components of the scouring phenomenon occurrences. To achieve an optimal solution, the effectiveness of the chemical stabilization method involving cement, bentonite, micro- silica, and synthesized nano-titanium additives was evaluated through an oedometer, Atterberg limits, uniaxial compression, and direct shear tests. Additives dry mixing of cement and nano-titanium were obtained as the optimal stabilization solutions against scouring compared to other additives. However, considering the environmental impacts of cement production and use, nano-titanium presents a more environmentally sustainable option due to CO2 absorption and reduced damage potential to vegetation.

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in agriculture, which increased the risk to soilplant systems. Studies have demonstrated that TiO2 NPs can induce phytotoxicity. However, the toxicity mechanisms, particularly under the stress of TiO2 NPs with different crystalline forms, remain inadequately reported. In this study, we combined transcriptomics and metabolomics to analyze the toxicity mechanisms in rice (Oryza sativa L.) under the stress of anatase (AT) or rutile (RT) TiO2 NPs (50 mg/kg, 40 days). The length (decreased by 1.1-fold, p = 0.021) and malondialdehyde concentration (decreased by 1.4-fold, p = 0.0027) of rice shoots was significantly reduced after AT exposure, while no significant changes were observed following RT exposure. Antioxidant enzyme activities were significantly altered both in the AT and RT groups, indicating TiO2 NPs induced rice oxidative damage (with changes of 1.1 to 1.4-fold, p < 0.05). Additionally, compared to the control, AT exposure altered 3247 differentially expressed genes (DEGs) and 56 significantly differentially metabolites in rice (collectively involved in pyrimidine metabolism, TCA cycle, fatty acid metabolism, and amino acid metabolism). After RT exposure, 2814 DEGs and 55 significantly differentially metabolites were identified, which were collectively involved in fatty acid metabolism and amino acid metabolism. Our results indicated that AT exposure led to more pronounced changes in biological responses related to oxidative stress and had more negative effects on rice growth compared to RT exposure. These findings provide new insights into the phytotoxic mechanisms of TiO2 NPs with different crystalline forms. Based on the observed adverse effects, the study emphasizes that any form of TiO2 NPs should be used with caution in rice ecosystems. This study is the first to demonstrate that AT is more toxic than RT in paddy ecosystems, providing crucial insights into the differential impacts and toxic mechanisms of TiO2 NPs with different crystalline forms. These findings suggest prioritizing the use of RT when TiO2 NPs are necessary in agricultural development to minimize toxicity risks.

Titanium dioxide nanoparticles (TiO2 NPs) are among the most commonly used nanomaterials and are most likely to end up in soil. Therefore, it is pertinent to study the interaction of TiO2 NPs with soil microorganisms. The present in vitro broth study evaluates the impacts of low-dose treatments (0, 1.0, 5.0, 10.0, 20.0, and 40.0 mg L-1) of TiO2 NPs on cell viability, morphology, and plant growth promoting (PGP) traits of rhizobia isolated from mung bean root nodule. Two types of TiO2 NPs, that is, mixture of anatase and rutile, and anatase alone were used in the study. These TiO2 NPs were supplemented in broth along with a multifunctional isolate (Bradyrhizobium sp.) and two reference cultures. The exposure of TiO2 (anatase+rutile) NPs at low concentrations (less than 20.0 mg L-1) enhanced the cell growth, and total soluble protein content, besides improving the phosphate solubilization, Indole-3-acetic acid (IAA) production, siderophore, and gibberellic acid production. The TiO2 (anatase) NPs enhanced exopolysaccharide (EPS) production by the test rhizobial cultures. The radical scavenging assay was performed to reveal the mode of action of the nano-TiO2 particles. The study revealed higher reactive oxygen species (ROS) generation by the TiO2 (anatase) NPs as compared with TiO2 (anatase+rutile) NPs. Exposure to TiO2 NPs also altered the morphology of rhizobial cells. The findings suggest that TiO2 NPs could act as promoters of PGP traits of PGP bacteria when applied at appropriate lower doses.

During the COVID-19 pandemic, an abundance of plastic face masks has been consumed and disposed of in the environment. In addition, substantial amounts of plastic mulch film have been used in intensive agriculture with low recovery. Butyl benzyl phthalate (BBP) and TiO2 nanomaterials (nTiO2) are widely applied in plastic products, leading to the inevitable release of BBP and nTiO2 into the soil system. However, the impact of coexposure of BBP and nTiO2 at low concentrations on earthworms remains understudied. In the present study, transcriptomics was applied to reveal the effects of individual BBP and nTiO2 exposures at a concentration of 1 mg kg -1, along with the combined exposure of BBP and nTiO2 (1 mg kg -1 BBP + 1 mg kg -1 nTiO2 (anatase)) on Metaphire guillelmi. The result showed that BBP and nTiO2 exposures have the potential to induce neurodegeneration through glutamate accumulation, tau protein, and oxidative stress in the endoplasmic reticulum and mitochondria, as well as metabolism dysfunction. The present study contributes to our understanding of the toxic mechanisms of emerging contaminants at environmentally relevant levels and prompts consideration of the management of BBP and nTiO2 within the soil ecosystems.