Alternative methods of aqueous chromium removal have been of great research interest in recent years as Cr (VI) is a highly toxic compound causing severe human health effects. To achieve better ...removal of Cr (VI), it is essential to understand the chemical reactions that lead to the successful removal of Cr species from the solution. Recent studies have demonstrated that graphene oxide (GO) based polymer beads cannot only adsorb Cr (VI) via electrostatic attractions but also reduce it to Cr (III), which is a much less toxic form of chromium. This conversion and the functional groups involved in this conversion, until now, were not elucidated. In the present study, we employed X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy to investigate the conversion pathway of Cr (VI) to Cr (III) in graphene-based polymer beads. The results showed that alcoholic groups are converted to carboxylic groups while reducing Cr (VI) to Cr (III). The inclusion of GO in the polymer beads dramatically increased the potential of Cr (VI) uptake and conversion to Cr (III), indicating polymers and nanomaterials containing alcohol groups can remove and convert chromium in water. Other functional groups present in the polymer bead play an important role in adsorption but are not involved in the conversion of Cr (VI) to Cr (III).
Increasing human activity, including commercial and noncommercial use of pharmaceuticals, personal care products, and agricultural products, has introduced new contaminants that can be challenging to ...remove with currently available technologies. Pharmaceuticals, in particular, can be especially challenging to remove from the water supply and can pose great harm to people and local ecosystems. Their highly stable nature makes their degradation with conventional water treatment techniques difficult, and studies have shown that even advanced treatment of water is unable to remove some compounds. As such, decontamination of water from pharmaceuticals requires the development of advanced technologies capable of being used in indirect and direct potable water reuse. In this review, we discuss pharmaceutical removal in indirect potable water treatment and how recent advancements in adsorption and photocatalysis technologies can be used for the decontamination of pharmaceutical-based emerging contaminants. For instance, new materials that incorporate graphene-based nanomaterials have been developed and shown to have increased adsorptive capabilities toward pharmaceuticals when compared with unmodified graphene. In addition, adsorbents have been incorporated in membrane technologies, and photocatalysts have been combined with magnetic material and coated on optical fibers improving their usability in water treatment. Advancements in photocatalytic material research have enabled the development of highly effective materials capable of degradation of a variety of pharmaceutical compounds and the development of visible-light photocatalysts. To understand how adsorbents and photocatalysts can be utilized in water treatment, we address the benefits and limitations associated with these technologies and their potential applicability in indirect potable water reuse plants.
The increased demand for cladding in high-rise buildings has prompted engineers to explore alternative products utilizing recycled materials. However, ensuring fire compliance in these alternative ...claddings, which are predominantly composed of low-volume polymer-based composites, poses a critical challenge. Traditional experimental methods for fire evaluation are costly, time consuming, and environmentally impactful. Considering this, a numerical approach was proposed for evaluating the fire performance of glass-polymer composite materials, which contain a high proportion of recycled glass and a lower percentage of rigid polyurethane. A cone calorimeter test was simulated using Computational Fluid Dynamics (CFD) software to investigate the flammability of the novel glass–polymer composite material. This validated numerical model was employed to assess the combustibility of the glass–polyurethane composite materials and identify influential parameters using the Design of Experiments (DoE) method. Statistical analysis revealed that three material properties, namely, the heat of combustion, the absorption coefficient, and the heat of reaction, significantly influenced the peak heat release rate (pHRR) of the glass–polyurethane composite materials compared to other properties. Based on these findings, an empirical equation was proposed that demonstrates a reasonable correlation with the pHRR of low-polymer recycled glass composite materials. The outcomes of this study hold considerable importance for understanding and predicting the combustibility behaviour of low-polymer–glass composites. By providing a validated numerical model and identifying critical material properties, this research contributes to the development of sustainable fire safety solutions for buildings, enabling the use of recycled materials and reducing reliance on conventional claddings.
•Urbanization impact ESVs the greatest.•Analyzed and predicted wetland change using the LCM.•Sensitivity Index shows LUC change has a positive impact on ESVs.
Understanding the effect of urbanization ...on urban wetland ecosystem service value (ESV) can provide scientifically sound information for urban planning and the protection of urban wetlands. This study aimed to discuss the effect of urbanization on the Bolgoda wetland, located in the Colombo Metropolitan Region (CMR), Sri Lanka. We developed a framework to evaluate the ESV changes based on land use/cover (LUC) changes between 1989 and 2021. Considering Natural Growth (NG) and Wetland Protection (WP) scenarios, we projected the future LUC changes (2030 and 2050) and evaluated the future ESV changes. The results revealed that the ESV has declined by USD 116 million/year from 1989 to 2021. The scenario analysis indicated that the ESV will continue to decrease by USD 17 million/year in 2030 and USD 35 million/year in 2050 under the NG scenario. However, under the WP scenario, the decrease would only be about USD 0.96 million/year in 2030 and USD 11 million/year in 2050, respectively. The most important ecosystem service functions are water regulation, genetic resources, food production, and climate regulation. Therefore, the local government should practice wetland management strategies to enhance the ESV of the Bolgoda wetland and other urban wetland ecosystems (UWEs) in the country.
•We use Smoothed Particle Hydrodynamics to model immiscible flow in a micromodel.•We model flow for a wide range of Capillary numbers and viscosity ratios.•We use results of laboratory experiments to ...validate the SPH model.•The SPH model accurately describes viscous and capillary fingering and stable displacement.
We have conducted a series of high-resolution numerical experiments using the Pair-Wise Force Smoothed Particle Hydrodynamics (PF-SPH) multiphase flow model. First, we derived analytical expressions relating parameters in the PF-SPH model to the surface tension and static contact angle. Next, we used the model to study viscous fingering, capillary fingering, and stable displacement of immiscible fluids in porous media for a wide range of capillary numbers and viscosity ratios. We demonstrated that the steady state saturation profiles and the boundaries of viscous fingering, capillary fingering, and stable displacement regions compare favorably with micromodel laboratory experimental results. For a displacing fluid with low viscosity, we observed that the displacement pattern changes from viscous fingering to stable displacement with increasing injection rate. When a high viscosity fluid is injected, transition behavior from capillary fingering to stable displacement occurred as the flow rate was increased. These observations are also in agreement with the results of the micromodel laboratory experiments.
Difficulties in direct monitoring of nitrate balance in agricultural fields reveal the importance of modeling and quantifying the affecting parameters on nitrate balance. We constructed meta-models ...for APSIMX-Sugarcane using the treed gaussian process and conducted a global sensitivity analysis for nitrate uptake and leaching under three conditions: (1) bare land (BL) to examine the influence of soil hydraulic characteristics, (2) N-free treatment under radiation use efficiency (RUE) ranges (i) 1.2–1.8 N-free(a) and (ii) 1.8–2.5 N-free(b), and (3) urea conditions to examine the influence of plant growth. Generated meta-models showed good accuracy (for all conditions: R2 > 0.70; NRMSE < 16%; AI > 0.90). The most influential parameters (sensitivity indices ≥ 0.02) were as follows: for leached NO3−N in BL: the parameter rerated to saturated flow-proportion of water between saturation and field capacity (SWCON) of all soil layers; for NO3− uptake and leached NO3−N in N-free(a) and urea: RUE of the phenological stage (PS) 3 (RUE3) and 4, tt_emerg_to_begcane, green_leaf_no, and y_n_conc_crit_leaf of PS 4 (NCL4); in N-free(b): RUE3, NCL4, and SWCON of soil layers 0–15 cm; 15–30 cm, which confirmed that influential parameters were depended on N-stress. The outcomes of this study are useful for enhancing the accuracy and efficiency of crop modeling.
Intestinal obstruction due to internal herniation of the bowel is a rare clinical entity which is often overlooked in the differential diagnosis of patients with abdominal pain who have no previous ...history of abdominal surgery. Several sites of bowel internal herniation have been described, amongst which internal herniation through the foramen of Winslow accounts for about 8% of cases. These patients present with nonspecific abdominal pain associated with symptoms of gastroesophageal reflux disease, and hence the diagnosis is often overlooked. The usual symptoms of intestinal obstruction can be delayed, which results in a delay in diagnosis and gangrene of the herniated bowel segment. Abdominal radiographs and computed tomography are helpful in the diagnosis. Open reduction is the management of choice; however, laparoscopic reduction has also been attempted, with good results.
We report a case of a middle-aged Sri Lankan man who presented with features of gastroesophageal reflux disease, developed features of intestinal obstruction and was found to have a gangrenous small bowel loop which had herniated through the foramen of Winslow. Following needle aspiration and reduction of the herniated small bowel loop, the gangrenous part of the small bowel was resected and an ileoileal anastomosis performed. The large foramen of Winslow was partially closed with interrupted stitches. The patient made an uneventful recovery.
Since delayed diagnosis of bowel obstruction is detrimental, it is of utmost importance to diagnose it early. Because internal herniation of the small bowel through the foramen of Winslow presents with nonspecific symptoms including features of gastroesophageal reflux disease, as documented in several cases worldwide and also presented by our patient, there should be a high degree of suspicion of internal herniation of the bowel causing bowel obstruction and low threshold for extensive investigation of patients presenting with symptoms of gastroesophageal reflux disease which does not resolve with usual medication.
Methane and natural gas, if released in deepwater, undergo physico-chemical processes as they rise through the water column. In deepwater, these gases are likely to be converted into hydrates. These ...are dissociated into gas upon reaching shallower regions. The present model accounts for plume thermodynamics and hydrodynamics, and is integrated with the associated physico-chemical processes such as hydrate formation/dissociation, gas dissolution, hydrate dissolution, hydrate shell crumbling and reformation, heat and mass transfer inside gas bubbles, multiple-sized bubbles and their size change, and possible gas separation from the main plume. The model simulations compare well with field data from Deepspill in Norway, and the gas bubble releases off the California coast. The scenario simulations show that the inclusion of multiple bubble sizes impacts the model results. Inclusion of hydrate dissolution is also important for deepwater releases. Without hydrate dissolution, the results tend to overestimate the hydrocarbon mass that will reach the water near the surface.
Groundwater pollution by nitrate leaching from sugarcane fields in Okinawa is recognized as a critical issue. Controlled release fertilizer (CRF) has the potential to reduce N leaching from cropping ...systems. The study focused on confirming the effectiveness of CRF at balancing sugarcane yield and reducing nitrate leaching from sugarcane fields via a water footprint (WF) approach. A lysimeter study was conducted using four treatments: (i) bare land, (ii) P and K fertilization without N, (iii) urea fertilization, and (iv) CRF application. According to the results, for both plant cane and ratoon, the total sugarcane dry weight obtained for CRF was higher compared to urea application. The cumulative nitrate-N leaching of the plant cane season for all treatments was higher than of the ratoon season. For the total crop cycle (plant cane plus ratoon), heavier nitrate-N leaching was observed in the urea-applied condition than in the CRF-applied condition. For both crop seasons, the total sugarcane WF of the CRF application (plant cane: 192.33 m3/t, ratoon: 190.47 m3/t) was lower than that of the urea application (plant cane: 233.47 m3/t, ratoon: 237.59 m3/t). WF values indicated that the CRF application had a lower impact on the groundwater of the area.
Food packaging plays an imperative role in the food processing sector by safeguarding foods from their point of harvesting until the moment of consumption. In recent years, biopolymers have attracted ...the attention of the scientific community as an alternative to conventional packaging materials. Among the available biopolymer sources, a lot of the focus has been on polysaccharides due to their superior barrier properties against gases, oils, and odors and their processing versatility. Moreover, there is also a growing interest in aliphatic polyester as a potential replacement for petrochemical-based synthetic plastics. Both polysaccharides and aliphatic polyesters have gained popularity in sustainable food packaging due to their unique characteristics, including their low cost, availability, biodegradability, gas and moisture barrier properties, film-forming capabilities, excellent heat resistance, and ability to be processed into films, trays, and coatings. This review highlights the structural features, properties, and recent advancements of several vital polysaccharides, namely, starch, chitosan, cellulose, alginate, pectin, carrageenan, and aliphatic polyesters, including polylactic acid (PLA) and polyhydroxybutyrate (PHB) for developing packaging materials, and their applications in the food industry. Conventional packaging and future perspectives of biopolymer-based food packaging are also comprehensively covered in this review.
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