The present paper describes the sono-assisted adsorption (sono-adsorption) of methylene blue (MB), methyl violet (MV), and Nile blue (NB) from aqueous solution by AC/CoFe₂O₄ magnetic composite. FT-IR, TGA-DTG, VSM, XRD, TEM, SEM, EDX, Map, and Raman analysis were used to characterize the magnetic composite. The magnetization saturation value of AC/CoFe₂O₄ magnetic composite was determined to be 53.06 emu/g. Dye sono-adsorption efficiency was increased by increasing adsorbent dose, pH value, and contact time, but not dye concentration. Pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were used to study the kinetic behavior of the cationic dye sono-adsorption. The sono-adsorption kinetics was reasonably followed by pseudo-second-order model (R² > 0.998). The results showed that the Freundlich model (R² > 0.976) was more able to describe the sono-adsorption equilibrium behavior than Langmuir, D-R, and Scatchard models. The maximum sono-adsorption capacity of NB, MV, and MB was determined as 86.24, 83.90, and 87.48 mg/g, respectively. Based on the parameters derived from isotherm modeling (RL, n, and E), the sono-adsorption process of cationic dyes is desirable and physical. An increase in NaCl concentration reduced the sono-adsorption efficiency for all dyes. Also, the adsorption-desorption of AC/CoFe₂O₄ magnetic was studied up to 10 stages, and it was confirmed that the sono-adsorption efficiency is acceptable up to the eight stage. AC/CoFe₂O₄ magnetic composite is, therefore, an affordable and recyclable adsorbent to remove the molecule of NB, MV, and MB dyes from aqueous media.

The acidification liquid of waste activated sludge (WAS) could be used as the additional carbon source of biological nutrient removal. Recently, the optimization of operating conditions for the acidification metabolites has attracted much attention. In this study, a three-factor Box-Behnken design (BBD) was applied to determine the relative importance of the various factors and the optimum operating during acidification using response surface method (RSM). The importance of the individual variables on the production of soluble chemical oxygen demand (SCOD) was suspended solids (SS) > shaking rate > initial oxidation-reduction potential (ORP). The increase on SS content led to a decrease on the acidification degree. Low SS could promote mass exchange and microbial activity. The maximum SCOD yield (9288.5 mg/L) was predicted under the optimum condition at 8.0 g/L SS, 144.0 mV initial ORP, and 60.0 r/min shaking rate. Also, the releasing of soluble protein and carbohydrate was calculated as responses. The individual effect of shaking rate and initial ORP had significant effect on soluble protein and carbohydrate releasing, respectively. This study would provide valuable information for increasing the efficiency of acidification.

The residential areas are located around one of the oldest and largest non-nuclear industrial cities in Saudi Arabia, Arabian Gulf. Therefore, it is important to study the radioactivity levels in the urban soil in order to estimate the potential risk of radiation in environment and for public. The activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in urban soil around non-nuclear industries were measured using gamma ray spectrometric technique. The mean values of activity concentrations were found to be 7.64 ± 0.4, 3.76 ± 0.2, 174 ± 3.7, and 0.391 ± 0.03 (Bq/kg) for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. Radium equivalent activity (Raₑq), gamma absorbed dose rate in air (D), and annual effective dose equivalent (E) for outdoor were calculated. The mean values of these radiological parameters were found to be less than the allowed limits in soil. The obtained results were compared with other studies from Arabian Gulf and other regions of the world. Consequently, the direct gamma radiation exposure from the urban soil in the study area was found to be safe for public. Additionally, the present study is the first in this area which could be used as a baseline for radioactivity levels in soil nearby industrial areas of the Arabian Gulf region.

The main objectives of the present study are to introduce new, ecologically safe, and natural compounds for controlling red flour beetle, Tribolium castaneum, and to understand the possible mode of action of these compounds. Therefore, the insecticidal and repellent activities of two phenylpropenes and six monoterpenes have been evaluated against the adults of T. castaneum. The inhibitory effects of these compounds on the activity of adenosine triphosphatases (ATPases) and acetylcholinesterase (AChE) were also tested. In fumigant toxicity assay, (−)-terpinen-4-ol (LC₅₀ = 20.47 μl/l air) and α-terpinene (LC₅₀ = 23.70 μl/l air) exhibited the highest toxicity without significant differences between them. Moreover, (−)-menthone and p-cymene showed strong toxicity, while (−)-citronellal, trans-cinnamaldehde, and eugenol were not active. In contact toxicity assay, the two phenylpropenes, trans-cinnamaldehde and eugenol, had the highest toxicity with same LC₅₀ value of 0.02 mg/cm². The monoterpenes and phenylpropenes showed pronounced repellent effect on the adults of T. castaneum at 0.001 mg/cm² with (−)-menthone, trans-cinnamaldehyde, and α-terpinene being the most effective after 2 h of exposure. Repellent activity depended on compound, exposure time, and concentration. On the other hand, the tested compounds exhibited strong inhibition of ATPases form the larvae of T. castaneum as their IC₅₀ values ranged between 1.74 and 19.99 mM. In addition, (−)-citronellal (IC₅₀ = 9.82 mM) and trans-cinnamaldehde (IC₅₀ = 23.93 mM) caused the highest inhibitory effect on AChE, while α-pinene (IC₅₀ = 53.86) and p-cymene (IC₅₀ = 68.97 mM) showed the weakest inhibitory effect. The results indicated that the tested phenylpropenes and monoterpenes had the potential to be developed as natural insecticides and repellents for controlling T. castaneum.

The soil permeability and underground water level greatly affect the performance of low-impact development (LID) practices. Shanghai is located in the area of estuary and is characterized by its high groundwater level and low soil infiltration rate. The LID practices in Fuxing Island Park, Shanghai, including a bioretention cell, swales, a permeable pavement, and a combined LID practices were studied in the present paper. The performance of LID practices during the period of eight rainfall events was evaluated in terms of hydrology and water quality. Due to the detention of the LID practices, a significant delay between the peak rainfall and the peak surface runoff was observed. On-site tests show it is suitable for the applicability of LID in a rainy city with low soil infiltration rate and high groundwater level. Moreover, the Stormwater Management Model (SWMM) was also used to compare the hydrologic effects before and after these four LID practices application in the park. Results indicated the LID practices could effectively reduce the runoff volume and the peak flow in the park. Furthermore, the runoff water quality evaluation showed the pollutants were effectively removed by these four LID practices due to both runoff treatment and flow volume reduction. The bioretention system proved to be effective as a result of its larger facility area while the swales had the obvious reduction volume both per facility area and per catchment area.

The evaluation of the toxicological effects of titanium dioxide nanoparticles (TiO₂NPs) is increasingly important due to their growing occupational and industrial use. Curcumin is a yellow curry spice with a long history of use in herbal medicine and has numerous protective potentials such as antioxidant, antimicrobial, anti-inflammatory, and anti-apoptotic effects. Accordingly, we tested the hypothesis that curcumin could ameliorate TiO₂NP-induced cardiotoxic and genotoxic effects in adult male albino rats. For this purpose, 48 adult male albino rats were randomized into five groups; all treatment was by oral gavage once daily for 90 days: group I (8 rats), untreated control; group II (16 rats), subdivided into vehicle control IIa (8 rats) received saline and vehicle control IIb (8 rats) received corn oil; group III (8 rats) orally gavaged with curcumin dissolved in 0.5 ml corn oil at a dose of 200 mg/kg b.w./day; group IV treated with TiO₂NPs at a dose of 1200 mg/kg b.w./day (1/10 LD₅₀) suspended in 1 ml of 0.9% saline; group V treated with curcumin + TiO₂NPs (the same previously mentioned doses). Curcumin was orally gavaged for 7 days before TiO₂NPs treatment was initiated, and then they received TiO₂NPs along with curcumin at the same doses for 90 days. TiO₂NPs administration resulted in several myocardial cytomorphic changes as structurally disorganized, degenerated, and apoptotic cardiomyocytes and the newly implemented 3-nitrotyrosine immune expression rendered strong evidence that these effects derived from the cardio myocellular oxidative burden. Furthermore, comet assay results confirmed TiO₂NP-related DNA damage. Remarkably, all these changes are partially mitigated in rats treated with both curcumin and TiO₂NPs. Our results suggest that concurrent curcumin treatment has a beneficial role in ameliorating TiO₂NP-induced cardiotoxicity and this may be mediated by its antioxidative property.

Road transport is the main source of pollution to the environment in urban areas; therefore, there is a need to accurately estimate the amount of exhaust gases emitted by motor vehicles. The development of systems for measuring emissions of exhaust gases caused the exit from stationary chassis dynamometers to real road test. This paper presents an analysis of emission data from the PEMS system for real driving cycles of various types of vehicles, complying with EURO2-EURO6 standards, fueled with petrol, LPG, and diesel in urban, rural, and motorway areas as well as detailing roundabouts. The results show that in the range of roundabouts, there is an increased emission of harmful exhaust components, such as CO₂, THC, CO, and NOx. Due to the specific traffic conditions that prevail at the roundabout (acceleration, braking, acceleration to a certain speed), the methodology for creating an exhaust emission model for this type of objects has been proposed. Statistical analysis of the received boosted regression tree models based on the coefficient of regression, root mean square error, and mean absolute error and based on the visual assessment of the results show that the obtained models are well represented by real data. The obtained results of emission calculations on roundabouts may be used to identify areas of increased emission of harmful exhaust components, as well as an introduction to prepare new roundabout design guidelines concerning emission data.

The CO₂ capture capacity and cyclic stability of calcium oxide (CaO) prepared from cockle shells (CS) were enhanced by incorporating rice husk (RH) and binder through wet-mixing method. The cyclic reaction of calcination and carbonation was demonstrated using thermal gravimetric analyzer (TGA) which the calcination was performed in a pure N₂ environment at 850 °C for 20 min and carbonation at 650 °C for 30 min in 20 vol% of CO₂ in N₂. The analysis using x-ray fluorescence (XRF) identified silica (Si) as the major elements in the sorbents. The RH-added sorbents also contained several types of metal elements such as which was a key factor to minimize the sintering of the sorbent during the cyclic reaction and contributed to higher CO₂ capture capacity. The presence of various morphologies also associated with the improvement of the synthesized sorbents performance. The highest initial CO₂ capture capacity was exhibited by CS+10%RH sorbent, which was 12% higher than the RH-free sorbent (CS). However, sorbents with the higher RH loading amount such as 40 and 50 wt% were preferred to maintain high capture capacity when the sorbents were regenerated and extended to the cyclic reaction. The sorbents also demonstrated the lowest average sorption decay, which suggested the most stable sorbent for cyclic-reaction. Once regenerated, the capture capacity of the RH-added sorbent was further increased by 12% when clay was added into the sorbent. Overall, the metal elements in RH and clay were possibly the key factor that enhances the performance of CaO prepared from CS, particularly for cyclic CO₂ capture. Graphical abstract Cyclic calcination and carbonation reaction

Atmospheric contamination by heavy metal(loid)–enriched particulate matter (metal-PM) is highly topical these days because of its high persistence, toxic nature, and health risks. Globally, foliar uptake of metal(loid)s occurs for vegetables/crops grown in the vicinity of industrial or urban areas with a metal-PM-contaminated atmosphere. The current study evaluated the foliar uptake of arsenic (As), accumulation of As in different plant organs, its toxicity (in terms of ROS generation, chlorophyll degradation, and lipid peroxidation), and its defensive mechanism (antioxidant enzymes) in spinach (Spinacia oleracea) after foliar application of As in the form of nanoparticles (As-NPs). The As-NPs were prepared using a chemical method. Results indicate that spinach can absorb As via foliar pathways (0.50 to 0.73 mg/kg in leaves) and can translocate it towards root tissues (0.35 to 0.68 mg/kg). However, health risk assessment parameters showed that the As level in the edible parts of spinach was below the critical limit (hazard quotient < 1). Despite low tissue level, As-NP exposure caused phytotoxicity in terms of a decrease in plant dry biomass (up to 84%) and pigment contents (up to 38%). Furthermore, several-fold higher activities of antioxidant enzymes were observed under metal stress than control. However, no significant variation was observed in the level of hydrogen peroxide (H₂O₂), which can be its possible transformation to other forms of reactive oxygen species (ROS). It is proposed that As can be absorbed by spinach via foliar pathway and then disturbs the plant metabolism. Therefore, air quality needs to be considered and monitored continuously for the human health risk assessment and quality of vegetables cultivated on polluted soils (roadside and industrial vicinity). Graphical abstract ᅟ

The objectives of this study were to investigate the response of cadmium (Cd) distribution and stability in soil aggregates as affected by applying different amendments and to understand the relationship between changes in soil aggregates and alleviation of Cd phytotoxicity to rice after amendment application. In the present study, rice (Oryza sativa L.) was cultivated on a Cd-polluted soil. Five soil amendments were applied, which are as follows: rice husk biochar (BC), Fe-added rice husk biochar (Fe-BC), attapulgite-based mixture (AM), zeolite-based mixture (ZM), and cow manure-based mixture (MM). The effect on Cd redistribution in soil and Cd accumulation in rice plant was evaluated. The results showed that the five amendments applied at the rate of 3% (w/w) significantly increased soil pH and decreased Cd mobility in soil and Cd accumulation in rice plants. The reduction rate of Cd content in rice grains ranged from 41 to 62% after amendment application. The remediation efficiency of the different amendments for decreasing Cd accumulation in rice tissues followed the order of Fe-BC > MM > BC > ZM > AM. Adding amendments promoted the formation of large aggregates (0.2–2.0 mm) with more mass loading of Cd and enhanced aggregate stability. Comparatively, Fe-BC was more effective than others for remediation of acid Cd-polluted paddy soil, as a significantly decreased Cd concentration in rice grain after its application was observed. Structural equation modeling (SEM) analysis revealed that DTPA-extractable Cd in small aggregates was the main factor affecting Cd accumulation in rice grain; soil pH directly affected aggregate stability; and aggregate stability was closely related to Cd availability in different size soil particles. These results indicated that the applied amendments were effective in reducing Cd bioavailability, most likely through raising the soil pH, improving aggregate stability, and re-distributing Cd from smaller soil aggregates to larger ones.