Highly efficient catalytic degradation of low-density polyethylene using a novel tungstophosphoric acid/kaolin clay composite catalyst

In order to take advantage of Bronsted acidity of tungstophosphoric acid(TPA) and Lewis acidity of kaolin, TPA loaded kaolin catalysts with varying percentages of TPA (10-50wt%) have been prepared by wet impregnation method. Fourier Transform Infra-Red Spectrometer, X-ray diffractometer, Brunauer-Emmett-Teller surface area analyzer, and Scanning Electron Microscope characterizations were performed to confirm the successful loading of TPA onKaolin. Catalytic cracking of low-density polyethylene (LDPE), by employing our TPA loaded Kaolin as the catalyst, produced a higher percentage of fuel oil (liquid and gaseous hydrocarbons) with negligible amount of semisolid wax (1.0 wt.%), significantly lower compared to the thermal cracking which produced ~22wt.% solid black residue. Moreover, GCMS analysis of oil showed that thermal cracking produces mainly higher hydrocarbons(C22) as compared to the catalytic cracking where larger fraction oflowerhydrocarbons were obtained. We purpose that the higher performance of our catalysts was due to the presence of both Bronsted and Lewis acid sites, which increase their catalytic efficiency and degraded the LDPE at the relatively lower temperatures. Our results suggest that prepared materials were effectivecatalysts with low cost and easily scalable production method; suitable for large-scale highperformance catalytic cracking of LDPE based materials

Synthesis, characterization and biological evaluation of three new Schiff bases derived from amino acids and their Ag(I) complexes

ABSTRACT. Three Schiff base ligands which were derived from glycine, asparagine and alanine L1, L2 and L3 were designed and used to synthesized their Ag(I) complexes. 1H NMR, FT-IR, UV-Visible and conductance techniques were used to characterize the ligands and their metal complexes. The synthesized compounds showed antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH). Schiff bases and their Ag(I) complexes were screened for antimicrobial activity, in vitro antibacterial activity against three gram negative bacteria Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi with two gram positive bacteria Staphylococcus aureus and Bacillus subtilis by micro plate almar blue assay (MABA), antifungal activity against Candida albicans and Candida glabrata by agar tube dilution protocol. In vitro anti-inflammatory activity was performed by heat induce denaturation method and in vivo anti-inflammatory activity was performed by induced paw edema method. Cytotoxicity of the synthesized compounds was recorded against cyclohexamide by MTT assay. Ag(I) metal complexes showed more significant biological activities as compared to ligands.                 KEY WORDS: Schiff bases, Metal complexes, Cytotoxicity, Antifungal, Antibacterial, Anti-inflammatory Bull. Chem. Soc. Ethiop. 2022, 36(1), 45-56.                                                                    DOI: https://dx.doi.org/10.4314/bcse.v36i1.5                                                       &nbsp

Synthesis and catalytic performance of cesium and potassium salts of aluminum substituted tungstoborate for pyrolysis of polyethylene waste to petrochemical feedstock

Polyoxometalates have gained considerable attention as a catalyst. Herein, we are reporting tungstoborate based catalysts for the conversion of waste polyethylene to liquid fuel. Novel cesium and potassium salts of aluminum substituted tungstoborate Keggin compounds were synthesized by a simple one-pot method and successfully characterized by FTIR, SEM-EDX, thermal analysis, NMR and single-crystal XRD. Catalytic cracking of waste polyethylene by using our prepared aluminum substituted catalysts (CsAB) showed 97% polymer conversion producing80 wt% of liquid hydrocarbons with a negligible amount of solid residue (∼3 wt%), significantly lower compared to thermal cracking where 22 wt% residue was produced. The oil collected at optimum reaction conditions (0.5 catalyst/polymer ratio and 3 h reaction time) was subjected to GC-MS analysis. The results showed that oil produced in catalytic cracking has a high selectivity to gasoline range hydrocarbons while thermal cracking showed selectivity to higher hydrocarbons (C13–C26). Olefin selectivity was also more prominent in catalytic cracking. Hence cesium and potassium salts of aluminum substituted tungstoborate are excellent catalysts for acid-catalyzed polymer cracking reactions to produce value-added petrochemicals

Studying reaction intermediates using IR spectroscopy

Chapter 1: Introduction A brief introduction to TRIR spectroscopy and its application to the study of reactive intermediates of organometallic complexes are provided. Chapter 2: The Photochemistry of Group VII NHC and Phosphine Complexes An introduction to the photochemistry of organometallic N-heterocyclic carbene complexes of the Group VII metals Mn and Re and a comparison with the analogous phosphine complexes is described. The photochemistry of the complexes has been studied using fast time resolved infrared spectroscopy (ns to IlS timescales). This Chapter explains the stability of metal-NHC bonds compared with metal-phosphine. The nature and reactivity of the intermediates of these complexes with alkanes in the presence of CO has been explained by analyzing a range of sterically different NHC complexes. Their rate constants have been determined in different alkane solvents to compare the reactivity of the phosphine and carbene complexes towards different alkanes. Evidence for the formation of agostic complexes is given. Chapter 3: Photochemical and Photophysical Investigation of fac-[Re(L)(COh( u- diimine)]" Complexes (where L = PPh3 or NHC) Rel( c-diimine) carbonyl complexes have great potential to act as infrared probes of DNA. The photophysics and photochemistry of fac-[Re(NHC)(CO))(a-diimine)t III complexes have been investigated by ps- and ns- TRIR spectroscopy. A comparison between both NHC and phosphine substituted Re(a-diimine) complexes is carried out. Moreover, the nature of the solvent and the substituent at the a-diimine has also been altered to study their effects on the energy of the excited states by emission and ns- and ps- TRIR spectroscopies. The 3MLCT excited state is found to be the lowest in energy in the fac-[Re(Iipr2Me2)(CO)3(dppz-F2)t complexes whilst the 3IL remains dominant for the other fac-[Re(Iipr2Me2)(CO)3(dppz)t complexes studied. A theoretical investigation using TD-DFT calculations into these complexes has been performed. Chapter 4: Investigation into the Photochemistry M«CF3hbpy)(COhX (M = Mn, Re and X = Br, Cl) This chapter focuses on the study of isomerization in M«CF3)2bpy)(CO)3X (M = Mn, Re and X = Br, Cl). The mer to fac isomerisation of Mn«CF3)2bpy)(CO)3Br in CH2Cb is investigated at room temperature using FTIR spectroscopy. The use of liquid CO2 at low temperature increases the life time of the intermediate and allows for the characterisation of a CO2-bound dicarbonyl species to be made. For the analogous Re complex, fac-Re«CF3)2bpy)(CO)3Cl, experiments were performed at low temperature in liquid CO2 and liquid CH2F2. Again,fac to mer isomerisation is observed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Spatial distribution and water quality index of Lahore Canal, Pakistan

The Lahore Canal (LC) in Lahore city of Pakistan, with the discharge of 402 cusecs, runs along the city's centre. With rapid urbanization and population growth, the LC water is deteriorating. This study determined the water quality index and spatial distribution of pollutants. Three months of sampling from six separate locations were performed. Water quality parameters were analysed. The results indicated that pH, solids, turbidity, hardness, alkalinity, and chlorides were within guidelines, but DO BOD and nitrogen were beyond guidelines. Moderate BOD values (2.24–8.06 mg/L) and low DO values (0.13–3.56 mg/L) indicated a low oxygen environment. Heavy metal concentration was as follows: Fe > Pb > Cr > Cu. The Pearson correlation coefficient indicated ± poor to moderate (0.3–0.7) correlation. The ANOVA result supported the alternative hypothesis, i.e., the pollutants originated from the same source. Principal component analysis and cluster analysis showed three primary sources for the different pollutants based on loading of variance and Euclidean distance, respectively. The WQI of LC at all locations was above 300, indicating that LC water is not suitable for any usage. The spatial distribution of parameters indicated the effects of urbanization and commercialization (small household industries) at Location-4. The poor water quality of LC needs immediate government attention. HIGHLIGHTS The Lahore Canal (LC) showed an abundance of organic matter as untreated wastewater is discharged continuously in it.; The source and correlation study indicated various urban and domestic sources as a point of origin.; The water quality index of LC was above 300 indicating the LC water is not suitable for any activity.; The spatial distribution of parameters indicated the effects of urbanization and commercialization.

Catalytic Pyrolysis of Low Density Polyethylene Using Cetyltrimethyl Ammonium Encapsulated Monovacant Keggin Units (C 19 H 42 N) 4 H 3 (PW 11 O 39 ) and ZSM-5

The effect of the catalysts on the pyrolysis of commercial low density polyethylene (LDPE) has been studied in a batch reactor. The thermal catalytic cracking of the LDPE has been done using cetyltrimethyl ammonium encapsulated monovacant keggin units (C 19 H 42 N) 4 H 3 (PW 11 O 39 ), labeled as CTA-POM and compared with the ZSM-5 catalyst. GC-MS results showed that catalytic cracking of LDPE beads generated oilier fraction over CTA-POM as compared to ZSM-5. Thus, the use of CTA-POM is more significant because it yields more useful fraction. It was also found that the temperature required for the thermal degradation of LDPE was lower when CTA-POM was used as a catalyst while high temperature was required for degradation over ZSM-5 catalyst. Better activity of CTA-POM was due to hydrophobic nature of CTA moiety which helps in catalyst mobility and increases its interaction with hydrocarbons

Catalytic Pyrolysis of Low Density Polyethylene Using Cetyltrimethyl Ammonium Encapsulated Monovacant Keggin Units C19H42N4H3(PW11O39) and ZSM-5

The effect of the catalysts on the pyrolysis of commercial low density polyethylene (LDPE) has been studied in a batch reactor. The thermal catalytic cracking of the LDPE has been done using cetyltrimethyl ammonium encapsulated monovacant keggin units (C19H42N)4H3(PW11O39), labeled as CTA-POM and compared with the ZSM-5 catalyst. GC-MS results showed that catalytic cracking of LDPE beads generated oilier fraction over CTA-POM as compared to ZSM-5. Thus, the use of CTA-POM is more significant because it yields more useful fraction. It was also found that the temperature required for the thermal degradation of LDPE was lower when CTA-POM was used as a catalyst while high temperature was required for degradation over ZSM-5 catalyst. Better activity of CTA-POM was due to hydrophobic nature of CTA moiety which helps in catalyst mobility and increases its interaction with hydrocarbons

Highly efficient catalytic pyrolysis of polyethylene waste to derive fuel products by novel polyoxometalate/kaolin composites

This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaolin) as polyethylene cracking catalysts. KAB/kaolin composites with varying concentrations of KAB (10–50 wt.%) were synthesized by the wet impregnation method and successfully characterized by Fourier-transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis and scanning electron microscopy with energy dispersive X-ray spectroscopy analytical techniques. Use of KAB loaded kaolin composites as the catalyst for low-density polyethylene (LDPE) cracking exhibited a higher percentage of polymer conversion (99%), producing 84 wt.% of fuel oil and negligible amount (˂ 1 wt.%) of solid residue while thermal cracking produced ~22 wt.% residue. Furthermore, gas chromatography–mass spectrometry analysis of oil obtained by non-catalytic cracking exhibited a high selectivity to high molecular weight hydrocarbons (C13–C23) compared to the catalytic cracking where 70 mol.% of gasoline range hydrocarbons (C5–C12) were produced. We propose that higher cracking ability of our prepared catalysts might ensue from both Brønsted and Lewis acid sites (from KAB and kaolin respectively), which enhanced the yield of liquid fuel products and reduced the cracking temperature of LDPE. These findings suggest that the prepared composites were cost-effective and excellent cracking catalysts that could be recommended for highly efficient conversion of waste plastic materials to petrochemicals at an industrial scale

Forensic Discrimination Potential of Blue, Black, Green, and Red Colored Fountain Pen Inks Commercially Used in Pakistan, by UV/Visible Spectroscopy, Thin Layer Chromatography, and Fourier Transform Infrared Spectroscopy

Examination and comparison of fountain pen inks are very important in forensic questioned documents examination in developing countries where the chances of fraud are greater in cases of cheques, marriage papers, entry of birth and death, etc. In this study, fountain pen inks of blue, black, green, and red colours that are commercially used in Pakistan have been discriminated by UV-Vis spectroscopy, TLC, and FTIR spectroscopy. We have calculated and compared the results in terms of discriminating power. UV/Visible Spectroscopy of fountain pen inks of different brands showed different composition despite their similar colours. TLC was effectively used to differentiate between the colored components of inks. FTIR results showed that each brand could be distinguished by studying the pattern of their absorption spectra that appeared due to the presence of different functional groups. On the basis of combined results of UV-VIS, TLC, and FTIR, the DP was found from 0.73-0.8 for blue, 0.80-1.0 for black, 0.5-1.0 for green, and 1.0 for red colored fountain pen inks. Overall, this study demonstrated the elevated worth of analysis of fountain pen inks commercially used in Pakistan as the study for fountain pen inks, while not very common, remains an interesting target study