Influence of the different oxidation treatment on the performance of multi-walled carbon nanotubes in the catalytic wet air oxidation of phenol

Clinical efficacy, safety, and cost of nine Chinese patent medicines combined with ACEI/ARB in the treatment of early diabetic kidney disease: A network meta-analysis

Objectives: To evaluate and compare the efficacy, safety, and cost of nine Chinese patent medicines (CPMs) combined with angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) in treating early diabetic kidney disease (DKD).

Design: Systematic review and network meta-analysis.

Data sources: PubMed, Embase, Cochrane Library, Web of Science, clinicaltrials.gov, SinoMed, Chinese Biomedicine, China National Knowledge Infrastructure, WanFang, and Chongqing VIP Information databases were comprehensively searched from the beginning to February 2022.

Review Methods: Randomized controlled trials (RCTs) including Bailing capsule (BLC); Jinshuibao capsule (JSB); Huangkui capsule (HKC); Compound Xueshuantong capsule (CXC); uremic clearance granule (UCG); Shenyan Kangfu tablet (SYKFT); tripterygium glycosides (TG); Keluoxin capsule (KLX), and Shenshuaining tablet (SSNT) combined with ACEI/ARB for patients with early DKD were reviewed.

Data Synthesis: Two reviewers independently screened articles, extracted data, and assessed the risk of bias. Risk ratios (RRs) and mean difference (MD) were reckoned to assess dichotomous variable quantities and continuous variable quantities, respectively. Using the surface under the cumulative ranking curve (SUCRA), we then ranked each therapeutic regime.

Results: Ultimately, 160 RCTs involving 13,365 patients and nine CPMs were included. UCG showed significantly higher probabilities on urinary albumin excretion rate (UAER) when compared with ACEI/ARB group, with MD of −47 (95%CI) (−57, −37) and SUCRA 98.0%. The CXC group achieved a remarkable improvement in overall response rate (ORR) compared with ACEI/ARB (RR, 1.3, 95%CI (1.2, 1.5)) with SUCRA 91.9%. SSNT could be significantly superior to ACEI/ARB group in terms of serum creatinine (Scr) (−19 (−26, −12), SUCRA 99.3%) and adverse effects (AEs) (0.46 (0.17, 1.1), SUCRA 82.9%). BLC showed the greatest effectiveness on 24 h urinary total protein (24 h UTP) (−170 (−260, −83), SUCRA 78.5%) and triglyceride (Trig) (−0.89 (−1.2, −0.53), SUCRA 97.0%). From the cost-effectiveness analysis of CPMs in China, the cost of TG, SYKFT and CXC was 108, 600, and 648 RMB, respectively, per 3 months and were ranked in the top three.

Conclusion: UCG and CXC might be the optimum selection for improving UAER and ORR, and SSNT could be significantly superior to ACEI/ARB group in terms of Scr and AEs. BLC shows the best curative effect on 24 h UTP and Trig. TG shows the highest cost-effectiveness among the nine CPMs.

Synthesis of hydrophilic carbon nanotube sponge via post-growth thermal treatment

Clean water is vital for healthy ecosystems, for human life and, in a broader sense, it is directly linked to our socio-economic development. Nevertheless, climate change, pollution and increasing world population will likely make clean water scarcer in the near future. Consequently, it becomes imperative to develop novel materials and more efficient ways of treating waste and contaminated water. Carbon nanotube (CNT) sponges, for example, are excellent in removing oleophilic contaminants; however, due to their super-hydrophobic nature, they are not as efficient when it comes to absorbing water-soluble substances. Here, by means of a scalable method consisting of simply treating CNT sponges at mild temperatures in air, we attach oxygen-containing functional groups to the CNT surface. The functionalized sponge becomes hydrophilic while preserving its micro- and macro-structure and can therefore be used to successfully remove toxic contaminants, such as pesticides, that are dissolved in water. This discovery expands the current range of applications of CNT sponges to those fields in which a hydrophilic character of the sponge is more suitable.

Enhancing electronic metal support interaction (EMSI) over Pt/TiO2 for efficient catalytic wet air oxidation of phenol in wastewater

Phenol is one of the major hazardous organic compounds in industrial wastewater. In this work, a highly active Pt/TiO₂ catalyst for catalytic wet air oxidation (CWAO) of phenol was obtained by supporting pre-synthesized Pt on TiO₂. During the followed hydrogen reduction, strong hydrogen spillover occurred without the migration of TiO₂ onto Pt. The reduced support then enhanced the electron transfer from TiO₂ to Pt, increasing the percentage of partially negative Pt (Pt^δ-), which has been confirmed by XPS. The strong EMSI made the obtained catalyst far more active than Pt/TiO₂ prepared by impregnation method. The electron-enriched Pt/TiO₂ achieved total organic carbon (TOC) conversion of 88.8% and TOF 149 h^-1 at 100 °C and 2 MPa O₂, while conventional Pt/TiO₂ gave TOC conversion of 39.5% and TOF 41 h^-1 for CWAO of phenol. Our work indicates that the enhancement of EMSI between metal and support can be an effective approach to develop highly active catalysts for phenol treatment.

Heavy metal ions and particulate pollutants can be effectively removed by a gravity-driven ceramic foam filter optimized by carbon nanotube implantation

It is of great significance to develop a new gravity-driven filter to remove water pollutants, but it is still challenging. Here, a novel and simple strategy is demonstrated to manufacture fly ash (FA) ceramic foams showing a three-dimensional interconnected porous structure, with multiwalled carbon nanotubes (MWCNTs) implanted by combining carbamate grafting and polydimethylsiloxane coating. The polydimethylsiloxane formed a physical coating on the carbamate group, generating an effective thermal insulating layer on the outer side of the entire MWCNT. The FA foam, which shows a sufficient adsorption capacity for Pb(II) (51.67 ± 1.17 mg g^-1) and Cd(II) (30.12 ± 0.37 mg g^-1) at pH = 5, T = 25 °C, has a 96.33%, 95.12%, 89.50% removal efficiency for Cd(II), Pb(II), and particulate pollutants, and exhibits excellent recycling performance. This paper provides new opportunities to fabricate gravity-driven filters with low energy consumption for wastewater treatment.

Heteroatom (N, S) Co-Doped CNTs in the Phenol Oxidation by Catalytic Wet Air Oxidation

The N, S-co-doping of commercial carbon nanotubes (CNTs) was performed by a solvent-free mechanothermal approach using thiourea. CNTs were mixed with the N, S-dual precursor in a ball-milling apparatus, and further thermally treated under inert atmosphere between 600 and 1000 °C. The influence of the temperature applied during the thermal procedure was investigated. Textural properties of the materials were not significantly affected either by the mechanical step or by the heating phase. Concerning surface chemistry, the developed methodology allowed the incorporation of N (up to 1.43%) and S (up to 1.3%), distributed by pyridinic (N6), pyrrolic (N5), and quaternary N (NQ) groups, and C–S–, C–S–O, and sulphate functionalities. Catalytic activities of the N, S-doped CNTs were evaluated for the catalytic wet air oxidation (CWAO) of phenol in a batch mode. Although the samples revealed a similar catalytic activity for phenol degradation, a higher total organic carbon removal (60%) was observed using the sample thermally treated at 900 °C. The improved catalytic activity of this sample was attributed to the presence of N6, NQ, and thiophenic groups. This sample was further tested in the oxidation of phenol under a continuous mode, at around 30% of conversion being achieved in the steady-state.

Iron oxide/carbon nanotubes/chitosan magnetic composite film for chromium species removal

An adsorbent in the form of a CLCh/MWCNT/Fe film was prepared using multiple walled carbon nanotubes (MWCNT) doped with magnetic iron oxide and deposited in crosslinked chitosan (CLCh). The CLCh/MWCNT/Fe was characterized by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), nitrogen (N₂) adsorption/desorption, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Infrared Spectroscopy (IR) and Raman Spectroscopy. The CLCh/MWCNT/Fe film presented a maximum adsorption capacity for Cr(III) of 66.25 mg/g (150 min) and for Cr(VI) of 449.30 mg/g (60 min) at 25 °C. The CLCh/MWCNT/Fe can be easily removed from the aqueous solution by a mechanical separation or by magnetization due to its magnetic properties. In ten consecutive reutilization adsorption cycles the CLCh/MWCNT/Fe film presented efficiency losses of only 12% and 6% for the removal of Cr(III) and Cr(VI), respectively.

Performance of various catalysts on treatment of refractory pollutants in industrial wastewater by catalytic wet air oxidation: A review

The tremendous increase of industrialization and urbanization worldwide causes the depletion of natural resources such as water and air which urges the necessity to follow the environmental sustainability across the globe. This requires eco-friendly and economical technologies for depollution of wastewater and gases or zero emission approach. Therefore, in this context the treatment and reuse of wastewater is an environmental friendly approach due to shortage of fresh water. Catalytic wet air oxidation (CWAO) is a promising technology for the treatment of toxic and non-biodegradable organic pollutants in the wastewater generated from various industries. Various heterogeneous catalysts have been extensively used for treatment of various model pollutants such as phenols, carboxylic acids, nitrogenous compounds and different types of industrial effluents. The present review focuses on the literature published on the performances of various noble and non-noble metal catalysts for the treatment of various pollutants by CWAO. Reports on biodegradability enhancement of industrial wastewater containing toxic contaminants by CWAO are reviewed. Detailed discussion is made on catalyst deactivation and their mitigation study and also on the various factors which affects the CWAO reaction.

Synthesis and characterization of an efficient and stable Al/Fe pillared clay catalyst for the catalytic wet air oxidation of phenol

A facile method for synthesizing Al/Fe pillared clays (PILCs) from natural bentonite clay, by using ultrasonic treatment during the aging and intercalation steps, has been established. Single metal (Fe-PILCs and Al-PILCs) and mixed metal (Al/Fe-PILCs, with varying compositions of the pillaring precursors) pillared clays were prepared and characterized with a combination of chemical and instrumental methods. The pillared clays were evaluated as catalysts in the catalytic wet air oxidation (CWAO) of phenol and the mixed metal pillared clay catalysts, especially with an Al/Fe ratio of 3 : 1, were found to be highly active and stable, with superior properties such as surface areas, basal spacing, high porosity and thermal stability. The catalysts could also be reused several times without significant loss of activity. The results of the study show that Al/Fe-pillared clay catalysts are effective catalysts for the oxidation of phenol and removal of TOC in aqueous solutions. The main intermediate products in the CWAO of phenol were hydroquinone, pyrocatechol, and benzoquinone and oxalic, formic, malonic, oxalic, malonic and maleic acids.

A facile method for synthesizing Al/Fe pillared clays (PILCs) from natural bentonite clay, by using ultrasonic treatment during the aging and intercalation steps, has been established.

Recent advances in nanomaterials for water protection and monitoring

Nanomaterials (NMs) for adsorption, catalysis, separation, and disinfection are scrutinized. NMs-based sensor technologies and environmental transformations of NMs are highlighted.

Oxygen-vacancy-promoted catalytic wet air oxidation of phenol from MnOx–CeO2

The presence of oxygen vacancies can promote the formation of active oxygen species, which is essential for phenol oxidation.

On the influence of various physicochemical properties of the CNTs based implantable devices on the fibroblasts' reaction in vitro

Coating the material with a layer of carbon nanotubes (CNTs) has been a subject of particular interest for the development of new biomaterials. Such coatings, made of properly selected CNTs, may constitute an implantable electronic device that facilitates tissue regeneration both by specific surface properties and an ability to electrically stimulate the cells. The goal of the presented study was to produce, evaluate physicochemical properties and test the applicability of highly conductible material designed as an implantable electronic device. Two types of CNTs with varying level of oxidation were chosen. The process of coating involved suspension of the material of choice in the diluent followed by the electrophoretic deposition to fabricate layers on the surface of a highly biocompatible metal-titanium. Presented study includes an assessment of the physicochemical properties of the material's surface along with an electrochemical evaluation and in vitro biocompatibility, cytotoxicity and apoptosis studies in contact with the murine fibroblasts (L929) in attempt to answer the question how the chemical composition and CNTs distribution in the layer alters the electrical properties of the sample and whether any of these properties have influenced the overall biocompatibility and stimulated adhesion of fibroblasts. The results indicate that higher level of oxidation of CNTs yielded materials more conductive than the metal they are deposited on. In vitro study revealed that both materials were biocompatible and that the cells were not affected by the amount of the functional group and the morphology of the surface they adhered to.

Study on Dispersion and Characterization of Functionalized MWCNTs Prepared by Wet Oxidation

The MWCNTs was functionalized by refluxing commercial MWCNTs (a-MWCNTs) in concentrated HNO3/H2SO4 (3:1 v/v) at 100°C for 6 hours. The dispersion of a-MWCNTs and functionalized MWCNTs (f-MWCNTs) were observed after 1 hour sonication in ethanol. Both samples were characterized by UV-vis spectroscopy for dispersion behavior. The dried f-MWCNTs and a-MWCNTs were characterized by Raman spectroscopy to estimate the defect level. The morphology of the samples were analyzed by Transmission Electron Microscopy (TEM). The f-MWCNTs was well dispersed in ethanol within 2 weeks of observations period. The colloidal stability of a-MWCNTs was low as it was easily sediment after 24 hours. The UV-vis spectra of f-MWCNTs show maximum absorbance at 250 nm meanwhile no absorbance was observed for a-MWCNTs. Analysis from Raman spectrum shows that the f-MWCNTs have relative intensity of 1.101 which is higher than a-MWCNTs that have relative intensity of 0.935. The image from TEM revealed that the f-MWCNTs have structural defects and the absence of amorphous carbon on sidewall meanwhile the a-MWCNTs indicate otherwise.

Graphene oxide as an effective catalyst for wet air oxidation of phenol

The graphene oxide (GO) and chemically reduced graphene oxides, used as catalysts in absence of any metals, were investigated in the catalytic wet air oxidation (CWAO) of phenol in a batch reactor. The characterization of the materials was measured with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman, fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The carbon materials exhibited good phenol and total organic compounds (TOC) removals in the CWAO of phenol. The GO had the highest catalytic activity, total phenol removal was achieved after 40 min, and ca. 84% TOC removal was obtained after 120 min at reaction temperature of 155°C, total pressure of 2.5 MPa and catalyst loading of 0.2 gL(-1).

Degradation of phenol via wet-air oxidation over CuO/CeO2-ZrO2 nanocatalyst synthesized employing ultrasound energy: physicochemical characterization and catalytic performance

Catalytic wet air oxidation (CWAO) of phenol was carried out under atmospheric pressure of oxygen at 160 degrees C in a stirred batch reactor over copper catalysts supported by CeO2-ZrO2. The copper with different loadings were impregnated over the composite support by a sonication process. The catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) specific surface area and Fourier-transformed infrared analyses. Characteristic peaks attributed to copper were not found in XRD patterns even at high loadings, but based on EDX results, the existence of copper particles was confirmed. It means that sonochemical synthesis method even at high loadings produced small copper particles with low crystallinity and excellent dispersion over the CeO2-ZrO2 composite. FESEM micrographs indicated just slight enhancement in particle size at high loadings of Cu. Blank CWAO experiments illustrated low conversion of phenol using bare CeO2-ZrO2 support. Although some agglomeration of particles was found at high loadings of copper but owning to the fact that almost all ZrO2 particles incorporated into the CeO2 lattice at high contents of Cu, catalyst activity not only did not decrease but also the phenol conversion reached to the higher values. The optimal catalyst loading for phenol degradation was found to be 9 g/l. Complete conversion of phenol was achieved using CuO/CeO2-ZrO2 in 9 g/l catalyst loading with initial phenol concentration of 1000 ppm after 3 h of reaction.