It is vital for the development and application of heavy metal stabilization/solidification (S/S) agents to reveal the mechanism of the reaction between water-soluble thiourea formaldehyde (WTF) resin and heavy metal and evaluate its repairing effect. Based on the density functional theory analysis of the WTF resin structure, the mechanism analysis and scanning electron microscope (SEM) showed that the three-dimensional network structure with thiocarbonyl and hydroxyl groups is very conducive to the capture of Cd²⁺. The reduction rate of Cd²⁺ in soil added WTF resin could reach 70.6%–86.0%. The result of BCR’s sequential extraction also proved that the 86.4%–94.1% of Cd in the soil repaired by WTF resin changed from acid-soluble state to residue state. Enzyme activity analysis and 16sRNA sequencing experiments showed that such a structure does not harm soil health. The urease and phosphatase tests showed the nitrogen and phosphorus cycle of the soil added WTF resin was repaired. Even compared with the remediation agents Na₂S and hydroxyapatite, WTF resin still performed better in repairing soil health. These findings provide valuable insights into the efficient causes of WTF resin and its harmless effects on soil. The results obtained provide a critical reference for the future application of practical and gentle heavy metal S/S agents.

Arsenic (As) is a ubiquitous environmental carcinogen that enters the human food chain mainly through rice grains. In the present study, we evaluated the potential of thiourea (TU; non-physiological reactive oxygen species scavenger) in mitigating the negative effects of arsenic (As) stress in indica rice variety IR64, with the overall aim to reduce grain As accumulation. At seedling stage, As + TU treatment induced the formation of more numerous and longer crown roots compared with As alone. The As accumulation in main root, crown root, lower leaf and upper leaf was significantly reduced to 0.1-, 0.14-, 0.16-, 0.14-fold, respectively in As + TU treated seedlings compared with those of As alone. This reduced As accumulation was also coincided with light-dependent suppression in the expression levels of aquaporins and photosynthesis-related genes in As + TU treated roots. In addition, the foliar-supplemented TU under As-stress maintained reducing redox conditions which decreased the rate of As accumulation in flag leaves and, eventually grain As by 0.53-fold compared with those of As treatment. The agronomic feasibility of TU was validated under naturally As contaminated sites of Nadia (West Bengal, India). The tiller numbers and crop productivity (kg seed/ha) of TU-sprayed plants were increased by 1.5- and 1.18-fold, respectively; while, grain As accumulation was reduced by 0.36-fold compared with those of water-sprayed control. Thus, this study established TU application as a sustainable solution for cultivating rice in As-contaminated field conditions.

Doping of nitrogen and sulfur on biochar (NS-B) was investigated by a novel and improved method for diethyl phthalate (DEP) removal. The preparation parameters including pyrolysis temperature and size of peanut shell biochar as well as thiourea/biochar mass ratio were selected as independent variables at three levels by applying the Box-Behnken design. The ANOVA results indicated that thiourea/biochar mass ratio exhibited the most significant effect. The comprehensive effects of the three factors on DEP removal efficiency were further elaborated, combining with the characterization results of the obtained NS-B materials. The formation of the pyridinic N and oxidized S groups examined by XPS was responsible for enhancing the DEP removal efficiency. The adsorption kinetic model fitting illustrated that large micropores and numerous adsorption sites improved the adsorption capacity of NS-B. According to the adsorption isotherm model fitting, NS-B (temperature 375 °C, size 300 mesh and thiourea/biochar mass ratio 0.1) possessed much higher maximum adsorption capacity for DEP (14.34 mg g⁻¹) than biochar (6.57 mg g⁻¹). NS-B exhibited excellent reusability towards DEP removal after five times recycling. Moreover, NS-B also had the potential in peroxydisulfate activation. These findings provide new insights into the environmental implications of NS-B.

A novel adsorbent, 3-phenyl-1-(2-pyridyl)thiourea (PPTU) was synthesized and its adsorption capabilities were studied for Cu(II), Cd(II), Ni(II), Pb(II) and Fe(II) cations in the waters such as tap and polluted seawaters. The kinetics, Langmuir and Freundlich isotherms were discussed related to the adsorptions. The adsorption capacities of PPTU were found 9.4; 12.6; 90.9; 57.1 and 30.4 mg g⁻¹ and preconcentration with PPTU including the FAAS step yielded the LOQ values 0.46; 2.65; 1.12; 2.65 and 1.72 ng mL⁻¹ for Cu(II), Cd(II), Ni(II), Pb(II) and Fe(II), respectively. The adsorbent after the elutions and washings could be reused three times in the next adsorptions. The interferences on the adsorptions arising from the major cations of the seawater and the usability of PPTU for interested metals in the seawater were discussed. The proposed method is simple with highly efficient and green preconcentration procedure for trace analysis of the target metal ions.

Delay sowing of wheat is a common problem in Punjab that exacerbates serious yield loss. To reduce yield loss and improve yield, different combinations of foliar-applied bioregulator and micronutrients, control (CK), zinc (Zn), boron (B), thiourea (TU), Zn + B (ZnB), Zn + TU (ZnTU), B + TU (BTU), Zn + B + TU (ZnBTU) were applied at booting and grain filling stages in delayed sown wheat in 2017–18 and 2018–19. The results showed that ZnBTU treatment significantly increased leaf area index by 25.06% and 23.21%, spike length by 15.11% and 19.65% in 2017 and 2018, respectively, compared to CK. The ZnBTU treatment also increased 1000-grain weight by 21.96% and 22.01% in 2017 and 2018, respectively, compared to CK. Similarly, higher Zn, B and N contents in straw and grain were recoded for ZnBTU treatment which was statistically similar to ZnB and ZnTU treatments. Overall, ZnBTU treatment also increased the photosynthetic rate, transpiration rate, stomatal conductance by 46.67%, 26.03%, 76.25% and decreased internal CO₂ by 28.18%, compared to CK, respectively. Moreover, ZnBTU also recorded the highest grain yield in 2017–18 (25.05%) and 2018–19 (28.49%) than CK. In conclusion, foliar application of ZnBTU at the booting and grain filling stages of delayed sown wheat could be a promising strategy to increase grain yield.

The effects of urea, (NH₄)₂SO₄, KNO₃, and NH₄NO₃ on nitrous oxide (N₂O) emission from soil at field capacity and submerged condition were studied during 120 days in the laboratory. Soils in both moisture regimes gave higher emissions in the beginning, which were reduced later. Total emission of N₂O was higher at submergence as compared to field capacity regardless of fertilizer type. At field capacity soil fertilized with ureaemitted the highest amount of N₂O (1903 μg N₂O-N kg⁻¹ soil) during 120 days while at submerged condition, soil with NH₄NO₃ gave the highest emission (4843 μg N₂O-N kg⁻¹ soil). In another study, the efficacy of seven nitrification inhibitors in reducing the emission of N₂O-N from soil fertilized with urea was tested in the laboratory. Nitrapyrin, 2-amino-4-chloro-6-methylpyrimidine (AM), and dicyandiamide (DCD) reduced the emission to 12, 24, and 63% that of urea, respectively, whereas sodium thiosulphate, sulphur, acetylene,and thiourea had no effect on emission of N₂O. In submerged conditions none of the inhibitors reduced the emission.

The total soluble protein-mediated morphological traits in mustard treated with Thiourea and Salicylic acid were investigated. In addition, it tested the hypothesis that the growth regulator salicylic acid protects the photosynthetic apparatus by up-regulating morphological traits. Under natural environmental conditions, seeds were sown in the field, and seed emergence was recorded. For three days after the 15-day stage, plants in the area were treated with thiourea and salicylic acid and allowed to grow for 90 days. Plants were harvested to assess various morphological traits. A follow-up application of SA and Thiourea plants improved plant height, leaf area, internodal length, leaf number, and accelerated plant activity. The up-regulation of morphological traits may have occurred in SA and Thiourea-mediated plants. After treatments, the level of total soluble protein was estimated in the leaves at proposed day intervals.

Adsorption of Rh(III) ions from the aqueous phase containing chloride ions was investigated batchwise using 1,3,5-triazine pentaethylenehexamine (TAPEHA) resin, which is highly resistant to strong acidic conditions. The effects of pH, temperature, initial concentration, and contact time on adsorption were examined. Rh(III) adsorption is favorable from the aqueous phase containing 3.0 and 0.1 M HCl. In both acidic cases, Langmuir is best fitting isotherm equation to system. The kinetics of Rh(III) adsorption on TAPEHA polymer was found to obey the pseudo-second-order kinetic equation, at both cases. Langmuir monolayer adsorption capacities were calculated as 327.03 and 113.76 mg/g in 3.0 and 0.1 M HCl, respectively. Experimental maximum adsorption capacities were measured as 198 and 100 mg/g in 3.0 and 0.1 M HCl, respectively. Due to different Rh(III) complexes with chlorine depending on acid concentrations, adsorption of Rh(III) from solutions containing 3.0 and 0.1 M HCl occurred via two different mechanisms; namely, ion exchange and surface complexation. The reuse of TAPEHA was also studied by column procedure, and the adsorption capacity of TAPEHA was not changed by using it five times. Adsorbed Rh(III) ions onto TAPEHA were completely eluted with thiourea 3% (w/v) in 1.0 M HCl. These findings showed that TAPEHA has a high resistance to acidic solutions and a higher Rh(III) uptake capacity than commercial adsorbents. Hence it can be used for rhodium recycling.

Poly(vinyl alcohol)/maleic anhydride/acryloyl thioamide monomer (PVA/MA/ATM) nanofiber membranes (NFm) were synthesized by a combination of UV radiation and an electrospinning technique. The PVA/MA/ATM NFm were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Brunauer–Emmert–Teller (BET) analysis, scanning electron microscopy (SEM), and energy dispersion spectrometry (EDS). These membranes were used for adsorption–desorption of platinum (Pt(IV)) and palladium (Pd(II)) from a fire assay (FA) leaching waste solution, and the effect of process parameters such as pH of solution, contact time, NFm dosage, temperature, and adsorption isotherms and kinetics studies on the recovery of Pt(IV) and Pd(II) from the waste solution were investigated. The adsorption equilibrium data fit better using the Langmuir model than the Freundlich model. Maximum adsorption capacities, Q ₘₐₓ, at 45 °C were found to be 69.93 and 112.36 mg/g for Pt(IV) and Pd(II), respectively. The activation energies (E ₐ) of Pt(IV) and Pd(II) were 27.90 and 20.29 kJ/mol, respectively. The best desorption reagent was a 1.0 M HCl–1.0 M thiourea (TU) solution for both Pd(II) and Pt(IV). Reusability studies showed that the adsorption capacity can remain up to 90 % after five times of usage. This study provides a promising NFm with an effective adsorption property for Pt(IV) and Pd(II) ions.

As well known, mercury is a toxic trace element due to its bioaccumulation and volatility which results in severe effects in health of ecosystems and humans’ life. Herein, for the first time, the synthesis of a N and S dual-doped waste-derived graphene-like nanoporous carbon via a facile and single-step route is presented and its capability in mercury vapor removal from gas streams is investigated. To prepare a modified adsorbent, thiourea was utilized as the doping agent to induce nitrogen and sulfur dopants into the nanoporous carbon structure derived from pyrolysis of cabbage (Capitat. var. Brassica oleracea) waste from Brassicaceae family as an inherently S, N-containing precursor, which is produced in noticeable amounts annually. The prepared adsorbents were characterized through FTIR, XRD, BET, SEM, TEM, and CHNOS techniques to get an insight into the structure, morphology, and chemical characteristics of the adsorbents. The structural characterization revealed the successful synthesis of a graphene-like nanoporous carbon sheet which was doped with nitrogen and sulfur atoms. The S, N dual-doped graphene-like carbon nanosheets showed an enhanced activity toward mercury vapor adsorption. For this end, two different dopant to carbon source ratios were considered and it was found that the higher dopant amount results in a better performance. From the adsorption experiments, it was revealed that the pristine graphene–like carbon had a less performance in mercury removal (71%) compared with doped samples (more than 90%) which shows the necessity of reinforcement and surface modification of as mentioned cabbage base graphene. However, the best sample which was prepared with the dopant to carbon ratio of 10 had a performance of 94.5% removal (2100 μg/g) compared with 89% (1980 μg/g) for mercury removal by the sulfur-impregnated commercial activated carbon.