Enhancing Water Purification by Integrating Titanium Dioxide Nanotubes into Polyethersulfone Membranes for Improved Hydrophilicity and Anti-Fouling Performance.

Water pollution remains a critical concern, one necessitated by rapidly increasing industrialization and urbanization. Among the various strategies for water purification, membrane technology stands out, with polyethersulfone (PES) often being the material of choice due to its robust mechanical properties, thermal stability, and chemical resistance. However, PES-based membranes tend to exhibit low hydrophilicity, leading to reduced flux and poor anti-fouling performance. This study addresses these limitations by incorporating titanium dioxide nanotubes (TiO2NTs) into PES nanofiltration membranes to enhance their hydrophilic properties. The TiO2NTs, characterized through FTIR, XRD, BET, and SEM, were embedded in PES at varying concentrations using a non-solvent induced phase inversion (NIPS) method. The fabricated mixed matrix membranes (MMMs) were subjected to testing for water permeability and solute rejection capabilities. Remarkably, membranes with a 1 wt% TiO2NT loading displayed a significant increase in pure water flux, from 36 to 72 L m2 h-1 bar-1, a 300-fold increase in selectivity compared to the pristine sample, and a dye rejection of 99%. Furthermore, long-term stability tests showed only a slight reduction in permeate flux over a time of 36 h, while dye removal efficiency was maintained, thus confirming the membrane's stability. Anti-fouling tests revealed a 93% flux recovery ratio, indicating excellent resistance to fouling. These results suggest that the inclusion of TiO2 NTs offers a promising avenue for the development of efficient and stable anti-fouling PES-based membranes for water purification.

Torrefaction interpretation through morphological and chemical transformations of agro-waste to porous carbon-based biofuel.

In the current study, two agro-waste lignocellulosic corncob (CC) and rice husk (RH) were thermally torrefied at 200-300 °C into a porous carbon-enriched biofuel. The scanning electron microscopy (SEM) of produced biofuel confirmed the rounded, homogenous, and spherical structure of the produced biofuels with higher porosity at a temperature between 250 and 300 °C with 60 min retention time. Brunauer-Emmett-Teller (BET) analysis indicated the high surface area (CC: 1.19-2.87 m2 g-1 and RH: 1.22-2.67 m2 g-1) and pore volume (CC: 1.23-2.81 ×10-3 m3 g-1 and RH: 1.46-2.58 ×10-3 m3 g-1). Crystallinity index decline percent (CC= 62.87% and RH=57.10%) estimated thermal stability and rise in amorphous cellulose reformation during (250-300 °C)/60 min that would efficiently hydrolyze during oxidative pyrolysis carbon reactive sites the rise in surface area and total pore's volume, having higher conversion rate as compared to raw materials. Carbon content was upgraded to 94% by eliminating hydrogen and oxygen from lignocellulosic agro-waste to produce energy-dense CC and RH. The lignin macromolecule transformation extent was estimated by O/C trend, which was equal to 63% and 47% for CC and RH, respectively, at 300 °C for 60 min. Due to low bulk density and pre-grinding energy requirements, torrefied biofuel with decomposed fibrous structure have lower transportation costs.

Enhancing CO2 separation from N2 mixtures using hydrophobic porous supports immobilized with tributyl-tetradecyl-phosphonium chloride [P44414][Cl].

The main obstacles in adopting solvent-based CO2 capture technology from power plant flue gases at the industrial scale are the energy requirements for solvent regeneration and their toxicity. These challenges can be overcome using new green and more stable ionic liquids (ILs) as solvents for post-combustion CO2 capture. In the current study, tributyl-tetradecyl-phosphonium chloride [P44414][Cl] as an IL, was immobilized on hydrophobic porous supports of polypropylene (PP), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) at 298 ± 3 K and pressures up to 2 bar. The surface morphology indicated homogenous immobilization of the IL on the membrane support. Supported ionic liquid membranes (SILMs) were tested for CO2 permeability and CO2/N2 selectivity. None of the SILMs exhibited IL leaching up to 2 bar. The PTFE-based SILM performed better than other supports with minimum loss in water contact angle (WCA) and achieved good antiwetting with a maximum CO2 permeability and selectivity over N2 of 2300 ± 139 Barrer and 31.60 ± 2.4, respectively. This work achieves CO2 permeability about two-fold more than other works having CO2/N2 selectivity range of 25-35 in similar SILMs. The diffusivity of CO2 and N2 in [P44414][Cl] was measured as 3.64 ± 0.18 and 2.01 ± 0.09 [10-8 cm2 s-1] and CO2 and N2 solubility values were 9.79 ± 0.47 and 0.19 ± 0.001 [10-2 cm3(STP) cm-3 cmHg-1], respectively. The high values of Young's modulus and tensile strength of the PTFE support-based SILM (234 ± 12 MPa and 6.07 ± 0.31 MPa, respectively) indicated the long-term application of SILM in flue gas separation. The results indicated phosphonium chloride-based ILs could be better solvent candidates for CO2 removal from large volumes of flue gases than amine-based ILs.

Synthesis and performance evaluation of copper and magnesium-based metal organic framework supported ionic liquid membrane for CO2/N2 separation.

The CO2 emission is enhancing drastically because of the continuous emission from industries and transport sector. Although the CO2 emission had decreased in the first half of 2020 by 8.8% due to COVID-19 restrictions however, it is again on the rise and it might exceed the estimated level in 2030. The current methods used for CO2 separation have serious operational and environmental constraints. To overcome these problems we have devised a supported ionic liquid membrane (SILM) incorporated with the blend of bimetallic metal-organic framework (MOF) of copper and magnesium ions (CuxMgx) and Trihexyltetradecylphosphonium chloride [P66614] [Cl] ionic liquid (IL). CuxMgx MOF were synthesized and characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and energy dispersive X-ray analysis (EDX). CuxMgx MOF with [P66614] [Cl] IL were immobilized on a flat sheet of polytetrafluoroethylene (PTFE) membrane. Single gas permeation tests of membranes loaded with 0.2/0.8 wt/wt% MOF/IL solution showed the highest CO2 permeability of 2937 Barrer and CO2/N2 selectivity of 33.26. The performance of SILM was also investigated with different water loadings of (30 wt % and 50 wt %) in addition to MOF/IL solution and at different feed pressure varying from 0.5 to 2 bars. Membranes showed enhancement in CO2 permeability to 3738 and 4628 Barrer whereas CO2/N2 selectivity decreased to 23.53 and 21.8 with membranes loaded with 30 and 50 wt % water, respectively, at a feed pressure of 2 bar. The gas permeation results show that the incorporation of CuxMgx MOF with IL in polymeric membrane enhances the CO2/N2 separation under humid conditions but slightly decreases CO2/N2 selectivity with an increase in feed pressure. The SILM synthesized in this research is highly viable for industrial flue gases because of the incorporation of phosphonium-based ILs that have high thermal stability.

Development of hybrid composite by integrating functionalized multi-walled carbon nanotubes (f-MWCNTs) with glass fiber reinforced polyester composite.

The current work presents the development of hybrid glass fiber reinforced polyester resin (GFRPs) composite. The composite integrates functionalized carbon nanotubes (f-MWCNTs) with glass fiber (GF) using polyester resin as a media. Hand lay-up method was adopted to prepare GFRPs samples in the form of rectangular sheets. Morphological characteristics of the GFRPs were investigated through scanning electron microscopy (SEM), to analyze the f-MWCNTs distribution and agglomeration of the developed composite's surface due to varying concentrations from 0.0 to 0.5 wt.%. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were performed to confirm the presence of f-MWCNTs in the developed GFRPs. Sample with 0.4 wt. % f-MWCNTs showed the highest tensile strength and impact energy of 79 MPa, indicating a 31.66% improvement and 1.6 Nm with 77% improvement, respectively as compared to the control sample (0.wt.% f-MWCNT). The same sample also showed the thermal stability till 390 °C as measured through thermogravimetric analysis (TGA). Deposition of extra 10 layers initially increased the composite strength from 40 MPa to 128 MPa, however further increase in layers to 15 resulted decrease in strength to 100 MPa due to the poor interaction between the polyester resin and GF. The addition of f-MWCNTs in the composite effectively strengthens the interfacial bonding, which significantly improved the tensile and impact strength of the composite, making it tougher and thermally stable. However, further increase in the concentration of f-MWCNTs degraded the mechanical properties of developed composite such as compressive strength because of agglomeration of these nanoparticles and void formation in the composite.

Challenges and issues with the performance of boron nitride rooted membrane for gas separation.

Various fillers such as zeolites, metal-organic framework, carbon, metal framework, graphene, and covalent organic framework have been incorporated into the polymers. However, these materials are facing issues such as incompatibility with the polymer matrix, which leads to the formation of non-selective voids and thus, reduces the gas separation properties. Recent studies show that hexagonal boron nitride (h-BN) possesses attractive characteristics such as high aspect ratio, good compatibility with polymer materials, enhanced gas barrier performance, and improved mechanical properties, which could make h-BN the potential candidate to replace conventional fillers. The synthesis of materials and membranes is the subject of this review, which focuses on recent developments and ongoing problems. Additionally, a summary of the mathematical models that were utilised to forecast how well polymer composites would perform in gas separation is provided. It was found in the previous studies that tortuosity is the governing factor for the determination of the effectiveness of a nanofiller as a gas barrier enhancer in polymer matrices. The shape of the nanofiller particles and sheets, disorientation and distribution of the nanofillers within the polymer matrix, state of aggregation and rate of reaggregation of the nanofiller particles, as well as the compatibility of the nanofiller with the polymer matrix all played a significant role in determining how well a particular nanofiller will perform in enhancing the gas barrier properties of the nanocomposites. For this purpose, this review has been focused not only on the experimentation work but also on the effect of tortuosity, exfoliation quality, compatibility, disorientation, and reaggregation of nanofillers.

Preparation of Small-Pore Ultrafiltration Membranes with High Surface Porosity by In Situ CO2 Nanobubble-Assisted NIPS.

The fabrication of ultrafiltration (UF) membranes with a small pore size (<20 nm) and high surface porosity is still a great challenge. In this work, a nanobubble-assisted nonsolvent-induced phase separation (BNIPS) technique was developed to prepare high-performance UF membranes by adding a tiny amount of CaCO3 nanoparticles into the casting solution. The phase inversion occurred in a dilute-acid coagulation bath to simultaneously generate CO2 nanobubbles, which regulated the membrane structure. The effects of the nano-CaCO3 content in the casting solution on the structure and performance of poly(ethersulfone)/sulfonated polysulfone (PES/SPSf) UF membranes were studied. The UF membrane prepared from a casting solution with 0.3% nano-CaCO3 achieved a surface porosity of 12%, a pore diameter of 10.2 nm, and a skin-layer thickness of 80.3 nm. The superior structure of the UF membrane was mainly attributed to the in situ generation of CO2 nanobubbles because the CO2 nanobubbles were amphiphobic to water and solvents to delay the phase inversion time and acted as nanosize porogens. The produced membrane showed an unprecedented separation performance, achieving a pure water permeance of up to 1128 L·m-2·h-1·bar-1, 2.5 fold that of the control membrane. Similarly, a high bovine serum albumin rejection of above 99.0% was obtained. The overall permeability and selectivity were better than those of commercial and other previously reported UF membranes. This work provides insight toward a simple and cost-effective technique to address the trade-off between pure water permeance and solute rejection of UF membranes.

Future advances and challenges of nanomaterial-based technologies for electromagnetic interference-based technologies: A review.

The emerging growth of the electronic devices applications has arisen the serious problems of electromagnetic (EM) wave pollution which resulting in equipment malfunction. Therefore, polymer-based composites have been considered good candidates for better EMI shielding due to their significant characteristics including, higher flexibility, ultrathin, lightweight, superior conductivity, easy fabrication processing, environmentally friendly, corrosion resistive, better adhesion with physical, chemical and thermal stability. This review article focused on the concept of the EMI shielding mechanism and challenges with the fabrication of polymer-based composites. Subsequently, recent advancements in the polymer composites applications have been critically reviewed. In addition, the impact of polymers and polymer nanocomposites with different fillers such as organic, inorganic, 2D, 3D, mixture and hybrid nano-fillers on EMI shielding effectiveness has been explored. Lastly, future research directions have been proposed to overcome the limitations of current technologies for further advancement in EMI shielding materials for industrial applications. Based on reported literature, it has been found that the low thickness based lightweight polymer is considered as a best material for excellent material for next-generation electronic devices. Optimization of polymer composites during the fabrication is required for better EMI shielding. New nano-fillers such as functionalization and composite polymers are best to enhance the EMI shielding and conductive properties.

Multi-ionic electrolytes and E.coli removal from wastewater using chitosan-based in-situ mediated thin film composite nanofiltration membrane.

This work presents the experimental investigation of flat sheet composite nanofiltration membrane synthesized with chitosan nanoparticles through interfacial polymerization of piperazine with trimesoyl chloride on polyethersulfone/sulfonated polysulfone substrates. The synthesized membrane was tested in wastewater treatment containing inorganic salts and E.Coli. Single binary electrolyte solution of KCl, MgCl2, MgSO4, and Na2SO4, ternary electrolyte solution, containing a combination of MgCl2 and MgSO4, KCl and MgCl2 and quaternary electrolyte solution of KCl, MgCl2, and MgSO4 as feed were treated in crossflow membrane cell for the water flux and species rejection in the permeate under operating pressure up to 0.5 MPa. The rejection of Na1+, K1+, Mg2+, Cl1-, and SO42- was observed to be 81, 28, 87, 96, and 98%, respectively with an average water flux up to 214 ± 10 L m⁻2.hr⁻1 in the permeate for the binary electrolyte solution. Similarly, the rejection for K1+, Mg2+, Cl1- and SO42- was noted to be 33, 94, 97, and 99%, respectively, for ternary electrolyte solution with an average water flux up to 211 ± 10 L m-2.hr-1. The quaternary ion system in the feed resulted in an average water flux up to 198 ± 12 L m⁻2.hr⁻1 with the rejection of K+, Mg+2, Cl- and SO4-2 as 35, 87, 96, and 99%, respectively. The model feed solution of E. coli after passing through the membrane achieved an E. coli rejection (99%) with water flux up to 220 L m-2.hr-1.

Protic/aprotic ionic liquids for effective CO2 separation using supported ionic liquid membrane.

Four ionic liquids (ILs) namely, 1-butylsulfonate-3-methylimidazolium P-toluene sulfonate ([BSmim][tos]), 1-butylsulfonate pyridine P-toluene sulfonate ([BSmpy][tos]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and 1-butylpyridine chloride ([Bpy][Cl]) were synthesized for the effective separation of gases CO2/N2 and CO2/CH4 through supported ionic liquid membranes (SILMs). ILs were confirmed by NMR and FTIR spectroscopy, and their characteristics and physical properties were studied. The ILs were immobilized on the porous hydrophobic 200 µm thick polyvinylidene difluoride (PVDF) support. Pure and mixed gas separation performances of the prepared SILMs were analyzed in a custom-built gas permeation unit. The SILMs were stable up to 0.6 MPa at room temperature without leaching the ionic liquid. [BSmim][tos] was recorded to have the highest solubility coefficient and permeability for CO2, among other ILs. At 0.5 MPa, for pure CO2/N2 and CO2/CH4, IL [BSmim][tos] was observed with selectivities of 56.2 and 47.5, respectively. Based on the SILMs separation performance, the ILs synthesized for this work can be ranked as [BSmim][tos] > [BSmpy][tos] > [Bmim][Cl] > [Bpy][Cl]. Moreover, the exceptionally high selectivity values of [BSmim][tos] and [BSmpy][tos] confirms the potential use of ILs for CO2 separation through SILMs.

Electrocatalytic CO2 fixation by regenerating reduced cofactor NADH during Calvin Cycle using glassy carbon electrode.

In this study, an enzymatic pathway has been developed to replicate the Calvin Cycle by creating the individual steps of the carbon cycle in a bioreactor. The technology known as "artificial photosynthesis" converts CO2 emissions into a variety of intermediates that serve as precursors to high-value products. CO2, light, water, and electricity were used as feedstock. An electrochemical reactor was also studied for the regeneration of active NADH operating at constant electrode potential. Initially, a batch electrochemical reactor containing 80 mL of 0.2 mM NAD+ in Tris-buffer (pH 7.40) was used to evaluate the electrode material operating at normal temperature and pressure. The results showed that the cathode is highly electrocatalytically efficient and selective to regenerate 97.45±0.8% of NADH from NAD+ at electrode potential of -2.3 V vs. mercury standard electrode (MSE). The NADH regeneration system was then integrated with ATP regeneration system and bioreactor containing Ribulose bisphosphate carboxylase/oxygenase (RuBisCO). NADH was regenerated successfully during the process electrochemically and then was used by the enzymatic reaction to produce triose phosphate and 3-Phosphoglycerate (3GPA).

CFD simulation of copper(II) extraction with TFA in non-dispersive hollow fiber membrane contactors.

This study presents computational fluid dynamics (CFD) simulation of dispersion-free liquid-liquid extraction of copper(II) with trifluoroacetylacetone (TFA) in hollow fiber membrane contactor (HFMC). Mass and momentum balance Navier-Stokes equations were coupled to address the transport of copper(II) solute across membrane contactor. Model equations were simulated using COMSOL Multiphysics™. The simulation was run to study the detailed concentration distribution of copper(II) and to investigate the effects of various parameters like membrane characteristics, partition coefficient, and flow configuration on extraction efficiency. Once-through extraction was found to be increased from 10 to 100% when partition coefficient was raised from 1 to 10. Similarly, the extraction efficiency was almost doubled when porosity to tortuosity ratio of membrane was increased from 0.05 to 0.81. Furthermore, the study revealed that CFD can be used as an effective optimization tool for the development of economical membrane-based dispersion-free extraction processes.

Association of clinical features of bone and joint lesions between children and parents with Kashin-Beck disease in Northwest China.

We investigated the clinical features of bone and joint lesions in children with Kashin-Beck disease (KBD) and the association of these features with their parents to determine specific clinical features for diagnosing KBD. A total of 2,248 children (4 to 18 years old) and their parents were examined by stratified cluster sampling from 33 villages in six endemic counties and from six villages in a non-endemic county. We collected individual information, clinical symptoms, and radiological signs of the right hand. KBD in children and their parents was assessed using the "Diagnosis Criteria of Kashin-Beck disease in China (WS/T207-2010)." Univariate and multivariate analyses were used to examine the correlation of clinical features between parents and offspring with KBD. The rates of clinical features in children were correlated with those in parents (P < 0.01). The parents of child cases had higher rates of clinical features than the parents of child controls. The prevalence of radiographic alterations in the distal end of the phalanges in the parents of child cases was significantly higher than that in the parents of child controls (father, χ (2) = 14.83, P = 0.001; mother, χ (2) = 10.41, P = 0.001). The parents of child cases were more likely to be KBD cases than the parents of controls (adjusted odds ratio, 4.4-12.1). Recognizing significant correlations in clinical features between children and their parents with KBD is helpful for early clinical diagnosis and evaluation of disease severity. Some clinical features of KBD, such as radiographic alterations in the distal end of the phalanges, might be useful for diagnosing KBD.

Frequency of Giardia lamblia infection in children with recurrent abdominal pain.

INTRODUCTION: To assess the frequency and causative role of Giardia lamblia infection in children with recurrent abdominal pain in our setup. METHODS: Prospective observational study of 239 children with recurrent abdominal pain was conducted at Department of Paediatrics, Postgraduate Medical institute, Hayatabad Medical Complex, Peshawar, from November 2004 to July 2006. Inclusion criteria was children from 4 to 14 years having recurrent abdominal pain defined as greater than three episodes of abdominal pain, in the last 3 months severe enough to affect the daily activities of the child. Fresh stool specimen was collected from each child for laboratory examination. Those with negative results had two other samples taken at different times. Positive cases were treated with metronidazole or tinidazole. Stool examination was repeated 1 week after the end of the treatment, followed by evaluation of complaints for the next 6 months. RESULTS: Seventy-four (30.96%) children were positive for giardiasis. Thirty-eight were positive in their first sample, while 27 and 9 were in their second and third samples respectively. Giardia cysts were positive in 93% and trophozoite in 7%. Mean age of positive cases was 86+/-47 months. The mean duration of pain was 158+/-64 days, with 42% having pain for more than 6 months. Abdominal cramps, nausea and vomiting, abdominal distension, flatulence/bloating, anorexia and weight loss were the main clinical symptoms observed. Poor health hygiene, poor toilet training, overcrowding, and low socioeconomic status were observed risk factors. Stools were negative for giardiasis one week after the end of treatment. Only 76% children returned for follow-up and all were free of any complaints. CONCLUSION: A significant proportion of children with recurrent abdominal pain were infected with Giardia lamblia and this study supports its potential role in recurrent abdominal pain in children.

Outcome of modified open surgery in tennis elbow.

BACKGROUND: Tennis elbow is a common disorder of upper extremity. It can be treated conservatively in majority of the patients but some resistant cases eventually need surgery. MATERIAL & METHODS: This descriptive study was conducted at Department of Orthopaedics, Ayub Teaching Hospital, Abbottabad, from January 2002 to June 2006. Sixteen patients had surgical release of the extensor tendon origin along with excision of the lateral epicondyle ridge. These patients did not respond to conservative treatment i.e. rest, non- steroidal anti inflammatory drugs (NSAIDS), local steroid injections and physiotherapy. Patients were followed upto six months. Outcome was graded as excellent, good and poor according to pain relief and function of the hand. RESULTS: Sixteen patients (17 elbows) were studied. Thirteen were female (81.25%) and three were male (18.75%). Fifteen patients (93.75%) had unilateral Tennis Elbow, while one had bilateral involvement (6.25%). In unilateral disease, right side was affected in eleven patients (68.75%) and left side in four (25%). Excellent outcome was noticed in eleven patients (68.75%) and good result in five patient (31.25%). CONCLUSION: Open surgical technique of releasing extensor tendon origin along with excision of lateral condylar ridge of the humerus is new and simple procedure and yields excellent and good result in patients with resistant Tennis Elbow.