Cadmium (Cd) is a widespread and strongly toxic environmental pollutant. In this study, the interaction between Cd and essential nutritional metals, such as iron (Fe) and zinc (Zn), was investigated in banana plants (Musa spp. cultivar Grand Nain), cultured in vitro, using Fourier-transform infrared (FT-IR) and physiological analysis. Plantlets were treated in vitro with Fe and Zn (200 and 500 mg/L) under 500 mg/L Cd exposure. The results showed that Cd toxicity increased Cd uptake and raised % of damage. However, Fe and Zn addition ameliorated the negative impact of Cd stress by reducing Cd and enhancing Fe, Zn, P, and K contents. The FT-IR analysis showed alterations within the bands correlated to the foremost macromolecules in plants under Cd stress and its interactions with Fe or Zn. The peaks of some functional groups at 3381.7 cm-1 for carbohydrates, proteins, alcohols, and phenolic compounds, 2922.02 cm-1 for lipids, 1643.97 cm-1 for amide I, 1517.46 cm-1 for amide II, 1057.63 cm-1 for cellulose and hemicellulose, and 616.94 cm-1 for aromatic compounds were negatively shifted by Cd stress. However, Fe and Zn regulated transmittance and intensity of these bands, showing improved tolerance to Cd. Moreover, Fe and Zn modulated the total antioxidants and enzymatic antioxidant activities for catalase and ascorbate peroxidase. The study concluded that the nutrition with Fe and Zn enhanced banana tolerance against Cd toxicity. It also highlighted the powerful role of FT-IR in understanding the mechanisms involved in minimizing Cd toxicity in banana shoots under Fe and Zn.

The application of alkali-activated slag (AAS) cementing material to the curing of soft soil foundations has a good engineering application prospect and is economical and environmentally friendly. In this study, three different activators (Na2OnSiO(2), NaOH, Ca(OH)(2)) were used to alkali-activate slag powder to solidify and improve soft soil in inland port areas. In order to explore the mechanical properties and strength formation mechanism of AAS-solidified soil under different activators, mechanical properties, and microscopic tests were carried out. Firstly, with unconfined compressive strength as the evaluation index, an orthogonal test of three factors, such as the type of activator, the amount of activator, and the amount of slag powder, was designed. Then, the unconfined compressive strength, resilience modulus, shear strength, and compression modulus of AAS-solidified soil were tested with the three activators under optimal dosage. Finally, phase composition, SEM-EDS, TG-DTG, and FT-IR analyses were carried out with the three AAS-solidified soils. The results show the following: (1) The factors affecting the unconfined compressive strength of AAS-solidified soil are ordered as follows: the type of activator > the amount of activator > the amount of slag powder. In addition, the optimal factors were as follows: activator type: Na2OnSiO(2); amount of activator: 3%; and amount of slag powder: 20%. (2) In considering the macroscopic mechanical properties, the effect of the activator is Na2OnSiO(2) > NaOH > Ca(OH)(2), and the Na2OnSiO(2) AAS-solidified soil has good early strength. (3) The hydration products of AAS are mainly C-A-S-H gel, N-A-S-H gel, and C-S-H gel, which increase the strength and cohesion of solidified soil. The results show that AAS-solidified soil with 0.7-modulus Na2OnSiO(2) as the activator has good engineering characteristics and can be used for curing soft soil foundations.

Purpose Fly ash (FA) is a waste byproduct produced in large quantities by coal-fired power stations. Its accumulation causes environmental issues, so it needs safe disposal of FA to reduce its accumulation. Herbal medicines like Mentha arvensis are being investigated worldwide for the prevention and treatment of a wide range of disorders because of their remarkable therapeutic benefits and absence of side effects when compared to current medications. Methods The aim of the study was to determine the effect of different concentrations of fly ash on growth, biochemical parameters, and constituents of essential oils of M. arvensis. Results The findings demonstrated that FA improved some important physical and chemical properties of soil. The use of FA-amended soil (10%) significantly improved the growth performance, photosynthetic pigments, protein, proline, antioxidant activity, and mineral contents. Conversely, the higher fly ash doses (25%) resulted in oxidative stress by increasing lipid peroxidation and electrolytic leakage levels, which negatively affected all of the aforementioned parameters. A confocal microscopic examination of the roots of M. arvensis revealed that fly ash at concentration of 25% resulted in membrane damage. In addition, alcohols, phenols, allenes, ketenes, isocynates, and hydrocarbons were among the functional groups found in the control and 10% of fly ash. Gas chromatography-mass spectrometry analysis of essential oils of M. arvensis treated with 10% fly ash revealed the presence of 32 bioactive components. Conclusions It is possible to use the 10% FA concentrations to increase plant growth and decrease the accumulation of FA that pollutes the environment.