Clean-soil Air Water最新文献

Crop responses to the application of urine fertilizer and ecosan manure may differ significantly in heterogeneous soils. Insufficient knowledge of the influence of soil texture on crop response to urine application and ecosan manure constitutes a knowledge gap that results in suboptimal crop yields. A detailed study of variations in soil texture and their interactions with urine fertilizer and ecosan manure is crucial for enhancing crop yield. The current study used a field experiment to quantify the response of maize to the application of urine fertilizer to soils with varying textures. A total of four treatments were used—chemical fertilizer (CF), urine fertilizer (U), ecosan (E), and control (C), which were replicated thrice in a completely randomized block design. Three sites with contrasting clay contents of 23%, 15%, and 10%, referred to as clay, intermediate, and sand sites, respectively, were used in the experiment. Plant biomass was measured a week after topdressing fertilizer application and harvesting. Soil physicochemical analysis was conducted to determine plant nutrient uptake and efficiency under various treatments. Maize grain yields ranged between 0.6 and 6.0 Mg ha⁻¹ across treatments. The U and CF treatments performed similarly at the clay site, whereas maize yield differed significantly between CF and U at the sandy site. Due to high water permeability, sandy soils lose nitrogen through leaching and volatilization, limiting nitrogen availability for plant growth. Soil texture therefore strongly influences urine fertilizer effectiveness on maize performance. This shows that soil texture needs to be considered when promoting urine fertilizer.

In this study, an iron-based metal–organic framework promoted cinnamon bark composite (FeMOF/CB) was synthesized and evaluated for the photocatalytic removal of rhodamine-B (RhB) under visible light irradiation (400–800 nm). Photocatalytic experiments were carried out using a catalyst dosage of 20 mg, an initial RhB concentration of 10 mg/L, and near-neutral pH conditions. The structural, functional, and optical properties of the prepared materials were characterized by SEM, FTIR, UV–Vis DRS, XRD, and BET analyses, revealing successful integration of FeMOF onto the CB surface and a narrow band gap of 2.10 eV. Under visible light irradiation, the FeMOF/CB composite achieved 94.52% RhB removal within 90 min, markedly outperforming pristine CB (55.33%). Mechanistic investigations, including pH-dependent studies, radical scavenging experiments, and kinetic analysis, indicated that the photocatalytic degradation process is predominantly governed by photogenerated holes (h⁺). Reusability tests demonstrated that FeMOF/CB retained over 70% of its initial efficiency after five successive cycles, confirming its structural stability and potential applicability in practical wastewater treatment systems.

Silk-based materials have emerged as potential candidates for removal of hazardous organic pollutants like dyes, pesticides, polyaromatic hydrocarbons, phenolic compounds, and pharmaceutical compounds from wastewater. The natural availability, biocompatibility, good mechanical strength, and biodegradability are some of the advantages that are offered by silk-based materials. Recently, research has been done to enhance the characteristics and stability of silk fibroins by crosslinking and mixing them with other macromolecules resulting in biodegradable silk-based composites with excellent removal efficiencies for toxic organic pollutants. This review goes beyond earlier studies on biopolymers like chitosan and cellulose by focusing on silk's unique protein-based structure and versatility. Further, recent studies focused on the characteristics and uses of most promising and efficient silk-based materials in the removal of commonly used hazardous synthetic and natural organic pollutants from wastewater have been systematically discussed. In addition, the mechanism of removal and reusability of silk-based materials has been highlighted. Further, the advantages and challenges in this direction and the future research perspectives have also been discussed.

Due to the increasing usage of plastics around the world, a significant number of microplastic particles have entered the environment. Human health is negatively impacted when microplastics (MPs) are present in water systems. This study presents the initial results of a 2024 survey on the concentration of microplastics in tap water samples in households in Vietnam's rural Red River Delta. Twenty-five tap water samples were collected from five different sampling sites; the samples were subsequently filtered, treated to remove organic matter, and analyzed for polymer identification. The results revealed an average of 6.8 microplastic particles per liter, with notable variation across samples, ranging from 2 to 16 particles per liter. The majority of fragment and fiber microplastics in the samples under observation were smaller than 200 µm. The polymer hazard index of the detected polymers indicates that the average polymer risk level in the tap water samples is 44.8, corresponding to pollution level III (high). These findings demonstrate the presence of microplastics in tap water, highlighting potential environmental and public health concerns. To mitigate these risks, drinking water treatment plants should implement techniques such as chemical coagulation, electrocoagulation, and membrane filtration. Future studies with larger sampling scales and more comprehensive analyses are needed to better assess and remove microplastics from tap water.

Microplastics (MPs) are ubiquitous across the globe. This study investigated atmospheric microplastic (AMP) and soil microplastic (SMP) pollution in five regions (Urumqi, Changji, Shihezi, Hutubi, and Manasi) of the “Wuchangshi” region, Xinjiang. AMPs were collected using pine needles as passive samplers, whereas SMPs were obtained from the soil surrounding pine trees. Results showed average abundances of AMPs and SMPs were 6.05 ± 2.13 n/g and 3088 ± 239 n/kg, respectively, with AMP abundances exceeding SMP abundances by 1.06 to 3.10 times. The highest AMP and SMP pollution levels in the five regions were Manasi (7.88 ± 1.48 n/g) and Shihezi (3680 ± 600 n/kg). The shape and size distribution of AMPs and SMPs were similar, with fiber accounting for the highest proportion. The color of MPs was primarily gray, and sizes were predominantly distributed between 1–3 mm. Polyethylene (PE) (25.7%)/polypropylene (PP) (20.6%) were the most prevalent polymers in AMPs/SMPs. Potential sources of atmospheric fibers and films primarily included residential areas, commercial districts, and transportation routes, whereas soil fragments and particles mainly originated from commercial districts. Pollutant load index (PLI) and the potential ecological risk index (PERI) indicated that Manasi exhibited relatively high MPs pollution levels among the five regions. This study aims to provide data references for urban MPs research and passive sampling of pine needles and enhance public awareness and understanding of MPs pollution in different environmental media within Xinjiang's urban areas.

This research focuses on the synthesis, characterization, and application of carbon dots derived from green apple peels (ACDots) immobilized onto titanium dioxide (TiO₂) The resulting TiO₂/ACDot composite exhibited remarkable adsorption efficiency for the removal of Victoria Blue R (VBR), as confirmed by kinetic and isotherm studies. Optimal adsorption conditions were achieved within 90 min, at pH 9.0. The composite, containing 9% (w/w) ACDots, attained 89.0% removal efficiency, outperforming pure TiO₂ by 20% at pH 9.0. It followed a pseudo second order kinetic model, while isotherm studies indicated a stronger correlation with the Langmuir model, revealing an adsorption capacity of 68.83 mg/g. In addition, the hybrid nanomaterial demonstrated high recyclability, effectively removing VBR even after three consecutive cycles. In contrast, the TiO₂/ACDot composite exhibited limited efficiency (14%) in adsorbing the anionic dye Reactive Black 5 (RB5) at pH 3.0, primarily due to favorable electrostatic interactions. This study highlights the synergistic advantages of incorporating low-cost, biowaste-derived carbon dots into hybrid nanomaterials, reducing dependence on expensive and chemically intensive synthetic processes. This work introduces a novel approach, demonstrating the potential of such hybrid materials as efficient, sustainable adsorbents for dye removal.

The disposal of spent coffee grounds (SCG) not only represents a significant waste of resources but also poses environmental challenges, highlighting the need for effective pretreatment strategies to mitigate potential adverse effects. Incorporating metal oxides into biomass-based adsorbents can enhance their adsorption capacity for heavy metal ions by enhancing electrostatic attraction and increasing the number of accessible active sites. In this study, KMnO₄-modified spent coffee grounds (KMnO₄-SCGS) were successfully synthesized and applied for the removal of Cd(II) from aqueous solution. Key process parameters, including contact time, pH, initial Cd(II) concentration, temperature, and adsorbent dosage, were systematically investigated. Characterization using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS) confirmed that KMnO₄ treatment increased the abundance of oxygen-containing functional groups and promoted the deposition of manganese oxides (MnO_x) on the adsorbent surface. The adsorption isotherm followed the Langmuir model, and the kinetics were well fitted by the pseudo-second-order model. The maximum Langmuir adsorption capacity of KMnO₄-SCGS for Cd(II) was determined to be 49.54 mg/g at pH 5.0, and 298 K. Thermodynamic analysis indicated that the adsorption process was spontaneous and endothermic. The enhanced Cd(II) uptake was primarily attributed to the synergistic effect of MnO_x and oxygen-containing functional groups, which facilitated the formation of surface complexes. In conclusion, KMnO₄ modification represents an effective strategy for developing high-performance adsorbents for Cd(II) removal.