Multifunctional carboxymethyl cellulose/graphene oxide/polyaniline hybrid thin film for adsorptive removal of Cu(II) and oxytetracycline antibiotic from wastewater.

The antibiotics and metal ions in the contaminated water bodies must be removed using appropriate methods for sustainable development. In this study, the multifunctional carboxymethyl cellulose/graphene oxide/polyaniline (CMC/GO/PANI) hybrid thin film was synthesized and utilized for adsorptive scavenging of (Cu(II) and oxytetracycline (OTC) from wastewater. The prepared thin films' morphology, chemical compositions, functionality, and surface charge were analyzed by well-known physicochemical techniques. The adsorption process of the selected model pollutants was examined as a function of reaction time, Cu(II), and OTC solution pH, concentrations, and temperatures. Results showed that CMC/GO/PANI hybrid thin film had higher Cu(II) and OTC adsorption than CMC, GO/CMC, and PANI/CMP thin films due to the multifunctional synergetic effect. The adsorption kinetic data were fitted to the pseudo-second-order model. Redlich-Peterson isotherm model well interpreted Cu(II) and OTC scavenging equilibrium data. Energetically, the adsorption was spontaneous and endothermic for both pollutants. The multifunctional CMC/GO/PANI thin film was recycled and reused seven times during adsorption-desorption cycles. The study outcomes demonstrated that CMC/GO/PANI thin film could be reused multiple times for large-scale wastewater purification.

A novel HIV model through fractional enlarged integral and differential operators.

This article presents a novel mathematical fractional model to examine the transmission of HIV. The new HIV model is built using recently fractional enlarged differential and integral operators. The existence and uniqueness findings for the suggested fractional HIV model are investigated using Leray-Schauder nonlinear alternative (LSNA) and Banach's fixed point (BFP) theorems. Furthermore, multiple types of Ulam stability (U-S) are created for the fractional model of HIV. It is straightforward to identify that the gained findings may be decreased to many results obtained in former works of literature.

Langevin Equations with Generalized Proportional Hadamard-Caputo Fractional Derivative.

We look at fractional Langevin equations (FLEs) with generalized proportional Hadamard-Caputo derivative of different orders. Moreover, nonlocal integrals and nonperiodic boundary conditions are considered in this paper. For the proposed equations, the Hyres-Ulam (HU) stability, existence, and uniqueness (EU) of the solution are defined and investigated. In implementing our results, we rely on two important theories that are Krasnoselskii fixed point theorem and Banach contraction principle. Also, an application example is given to bolster the accuracy of the acquired results.

Adsorption and photocatalytic scavenging of 2-chlorophenol using carbon nitride-titania nanotubes based nanocomposite: Experimental data, kinetics and mechanism.

Adsorption and interaction of pollutant species on surface of the catalyst materials play an important role on the photocatalysis process. Herein, experimental data on the adsorption behavior of 2-chlorophenol (2-CP) onto graphitic pure carbon nitride (C3N4), titania nanotubes (TiO2-NTs) and carbon nitride/titania nanotubes nanocomposite (C3N4/TiO2-NTs) from synthetic wastewater has been summarized. The data on photocatalytic degradation of the 2-CP under both ultraviolet (UV) and visible light irradiation is also presented. This work also evaluates the 2-CP scavenging efficiency of C3N4/TiO2-NTs nanocomposite prepared by calcination of 2 wt.% melamine with TiO2-NTs at 450 °C. The adsorption and photocatalysis experiments were conducted for 180 min at pH 7 with 100 mL solution of 2-CP (40 mg/L) and 0.05 g catalyst material. The acquired data can be valuable to identify the equilibrium time for 2-CP adsorption onto C3N4, TiO2-NTs, and C3N4/TiO2-NTs nanocomposite. Moreover, the obtained data can be useful to identify the suitable light source for the decomposition of 2-CP in the aquatic environment. The evaluated kinetic data might be significant for identifying the adsorption and photocatalysis reaction rate onto the applied catalyst materials. The obtained adsorption and photocatalysis data have been compared with that in literature to identify the adsorption and photocatalysis behavior of 2-CP on numerous catalysts at different experimental conditions.

A facile synthesis of bismuth oxychloride-graphene oxide composite for visible light photocatalysis of aqueous diclofenac sodium.

In this study, bismuth oxychloride/graphene oxide (BiOCl-GO) composite was fabricated by facile one pot hydrothermal method. The pure BiOCl and BiOCl-GO composite was characterized by X-ray diffraction, Transmission electron microscopy X-ray photoelectron spectroscopy and UV-Vis diffuse reflectance spectroscopy. The synthesized composite was then assessed for photocatalytic degradation of diclofenac sodium (DCF) in visible as well as direct solar light and UV irradiation. Results indicated that the photocatalytic removal efficiency of DCF was significantly affected by dose of catalysts, pH value and source of light. The results reveled that degradation efficiency of BiOCl-GO for DCF reduced from 100 to 34.4% with the increases in DCF initial concentration from 5 mg L-1 to 25 mg L-1. The solar light degradation of DCF using BiOCl-GO was achieved with apparent rate constant 0.0037 min-1. The effect of scavengers study revealed that superoxide ions and holes were mainly responsible for DCF degradation. The regeneration study indicates that BiOCl-GO composite can be successfully recycled up to the five cycles. The study revealed the effectiveness of one pot hydrothermal method for the fabrication of BiOCl-GO composite.

Experimental design and data on the adsorption and photocatalytic properties of boron nitride/cadmium aluminate composite for Cr(VI) and cefoxitin sodium antibiotic.

This article reports the experimental data on the adsorption and photocatalytic degradation-reduction properties of pure boron nitride (BN), cadmium aluminate (CdAl2O4) and boron nitride/cadmium aluminate (BN/CdAl2O4) composite for the hexavalent chromium (Cr(VI)) and cefoxitin sodium (CFT) in aqueous solution under the ultraviolet (UV) and visible light irradiation. This work evaluates the adsorption and photocatalytic efficiency of the 0.2g BN coupled with the CdAl2O4 in BN-0.2/CdAl2O4 composite for Cr(VI) and CFT. The experiments were performed by mixing the 0.025 material with 50 mL solution of known concentration (15 mg/L) at pH 3 for Cr(VI) and pH 7 for CFT. The obtained data can be valuable to select the proper light source (UV or visible) and pollutant to investigate the application of BN-0.2/CdAl2O4 composite. Moreover, presented data can help identify the equilibrium time for the adsorption process and to recognize the best process for the removal of the pollutants from wastewaters. A comparison of the obtained data with previously reported works has been conducted for the understanding of the adsorption and photocatalysis of Cr(VI) and CFT using various materials under the different experimental conditions.

Construction of a ternary g-C3N4/TiO2@polyaniline nanocomposite for the enhanced photocatalytic activity under solar light.

The combination of two or more semiconductor materials for the synthesis of new hybrid photocatalyst could be a good approach to enhance the visible light absorption, electron-hole (e-/h+) pair separation rate and photocatalytic decomposition of the organic contaminants. Herein, a facile in situ oxidative polymerization method has been used for the synthesis of visible light active g-C3N4/TiO2@polyaniline (g-C3N4/TiO2@PANI) nanocomposite for the decomposition of the congo red (CR) under the solar light irradiation. Prior to making the composite of TiO2 (P25) with g-C3N4 and polyaniline, a lamellar structure was generated onto the TiO2 brim by alkali hydrothermal treatment to enhance the surface area and adsorption properties. The PL and UV-visible analysis clearly showed the fast separation of the e-/h+ pair, and reduction in the bandgap energy of the g-C3N4/TiO2@PANI nanocomposite. The results revealed TiO2, PANI and g-C3N4 showed the synergestic behavior in the g-C3N4/TiO2@PANI nanocomposite and greatly enhanced the photocatalytic degradation of the CR. The photocatalytic decomposition of the CR was almost 100% for 20 mg/L at pH 5, 7 and 180 min. The reusability study of the spent catalyst showed the 90% degradation of CR after four consecutive cycles indicate that g-C3N4/TiO2@PANI nanocomposite is a stable and efficient catalyst. The high efficiency and reusability of the g-C3N4/TiO2@PANI nanocomposite could be attributed to the higher visible light absorption and sensitizing effect of the g-C3N4 and PANI.

Untapped potential of zeolites in optimization of food waste composting.

This study aims to examine the effect of zeolites in optimizing the process of food waste composting. A novel method of sequential hydrothermal was introduced to modify the natural zeolite and apply to in-vessel compost bioreactors. Raw and modified natural zeolites were applied at 10 and 15% (w/w) of the total waste and compared with un-amended control trial. Both raw and modified zeolites affected the composting process, but the notable results were observed for modified natural zeolite. The results for compost stability parameters were prominent at 15% modified natural zeolite concentration. The rapid and long-term thermophillic temperature and moisture content reduction to the optimum range was observed for modified natural zeolite. Furthermore, the total ammonium (NH4+) and nitrate (NO3-) concentration in modified natural zeolite were increased by 11.1 and 21.5% respectively as compared to raw zeolite. Compost stability against moisture contents (MC), electrical conductivity (EC), organic matters (OM), total carbon (TC), mineral nitrogen, nitrification index (NI) and germination index (GI) was achieved after 60 days of composting that was in accordance with the international compost quality standards. The findings of this study suggested the suitability of modified natural zeolite addition at 15% to the total waste as the optimum ratio for the composting of food waste in order to achieve a stable nutrient-rich compost.

Butterfly cluster like lamellar BiOBr/TiO2 nanocomposite for enhanced sunlight photocatalytic mineralization of aqueous ciprofloxacin.

The present study for the first time reports facile in-situ room temperature synthesis of butterfly cluster like lamellar BiOBr deposited over TiO2 nanoparticles for photocatalytic breakdown of ciprofloxacin (CIP). The butterfly cluster arrangement of BiOBr resulted in an increase in surface area from 124.6 to 160.797 m2·g-1 and subsequently increased incident light absorption by the composite photocatalyst. The XRD indicated the existence of TiO2 as spherical ≈10-15 nm diameter particles with [101] preferential growth planes of anatase phase while the lamellar BiOBr showing growth along [110] and [102] preferential planes that were also confirmed by the HR-TEM images. DRS data implicated 2.76 eV as the energy band gap of the synthesized nanocomposite while PL spectroscopic analysis predicted it to be 2.81 eV. XPS measurements examined the chemical oxidation states of the constituents among the nanocomposite samples. The lameller structure of BiOBr in 15%BiOBr/TiO2 acts as a manifold promoting both visible light (λ > 420 nm) and direct sunlight catalytic degradation of 25 mg·L-1 aqueous CIP up to 92.5% and 100%, respectively within 150 min. The rate constant values suggested that the visible light photocatalysis of CIP with 15%BiOBr/TiO2 was 5.2 and 9.4 times faster compared to pristine TiO2 and BiOBr, respectively. The free radical scavenging study demonstrated that although photogenerated superoxide ions and holes contribute to the overall photocatalytic activity, yet, hydroxyl radicals predominantly control the CIP oxidation. The synthesized nanocomposite was re-used up to five cycles and retained 82.98% efficiency even after 5th use cycle showing a decline of only 12%. The catalyst stability and easy recovery adds to its reusability and value of the photocatalytic process.

Novel Al2O3/GO/halloysite nanotube composite for sequestration of anionic and cationic dyes.

In this study, an Al2O3/graphene oxide/halloysite nanotube (Al2O3/GO/HNT) nanocomposite has been synthesized and used as an adsorbent for the sequestration of cationic methylene blue (MB) and anionic congo red (CR) dyes from wastewater. The properties of the synthesized Al2O3/GO/HNT were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Various factors such as pH, contact time, initial concentration and temperature have been investigated for evaluation of the optimum adsorption in the batch sorption experiment and experimental results showed the highest adsorption capacity was found to be 329.8 mg g-1 for CR and 258.4 mg g-1 for MB at an initial concentration of 500 mg l-1 which was three times higher than the individual Al2O3 GO and HNT concentrations. Freundlich and Langmuir adsorption isotherm models were fitted to the experimental data and the results implied that the adsorption of MB well described with Langmuir and CR is related to the Freundlich isotherm model. The kinetics data of CR and MB adsorption was well fitted to pseudo-first-order. The calculated values for thermodynamic parameters indicated that the MB and CR adsorption process were spontaneous and exothermic in nature. The effectiveness of the Al2O3/GO/HNT composite was also tested for adsorption of Cu(ii), oxytetracycline (OTC) antibiotic, and 2-chlorophenol (2CP) and the results revealed that the Al2O3/GO/HNT composite is a promising adsorbent for the dyes as well as heavy metals and other organic pollutants.

A Suzuki-type multivalued contraction on weak partial metric spaces and applications.

Based on a recent paper of Beg and Pathak (Vietnam J. Math. 46(3):693-706, 2018), we introduce the concept of H q + -type Suzuki multivalued contraction mappings. We establish a fixed point theorem for this type of mappings in the setting of complete weak partial metric spaces. We also present an illustrated example. Moreover, we provide applications to a homotopy result and to an integral inclusion of Fredholm type. Finally, we suggest open problems for the class of 0-complete weak partial metric spaces, which is more general than complete weak partial metric spaces.

Carbon nitride/titania nanotubes composite for photocatalytic degradation of organics in water and sludge: Pre-treatment of sludge, anaerobic digestion and biogas production.

In this study, carbon nitride/titania nanotubes (C3N4/TiO2 NTs) composites were synthesized for the enhanced visible light mediated photocatalytic degradation and pre-treatment of wastewater sludge for enhanced biogas production. The co-existence of C3N4 and TiO2 NTs and visible light activity was confirmed by XRD, TEM, UV-visible and PL spectroscopy. The photocatalytic performance of TiO2 NTs with 2% of melamine (precursor of C3N4), enhanced the degradation of 2-chlorophenol (2-CP) (k = 0.0176 min-1), where 96.6% removal was achieved at optimum pH 7.0 and 2-CP concentration of 30 mg/L. On the other hand, the application of C3N4/TiO2 NTs for solubilization of the rigid structure of sludge by photocatalysis released the soluble organics showing an improvement in sCOD production (4587 mg/L). Subsequently, anaerobic digestion of solubilized sludge has improved the methane production (723.4 ml kg-1 VS) by 1.37 and 1.6 times compared to that in anaerobic digestion with photolytic and raw sludge, thus showing a promising applicability for biogas production from sludge and wastewater treatment.

Synthesis of Cr2O3/C3N4 composite for enhancement of visible light photocatalysis and anaerobic digestion of wastewater sludge.

Visible light photocatalysts of Cr2O3/C3N4 composites (with different melamine concentrations) were prepared by high temperature calcination method. The composites samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy SEM, energy-dispersive X-ray spectroscopy (EDX), UV-visible spectroscopy and particle size analysis, which clearly indicated the coexistence of both Cr2O3 and C3N4 in the composites. The Cr2O3/C3N4 catalysts were tested for photocatalytic degradation of 2-chlorophenol in wastewater and solubilization of sludge in anaerobic digestion process to enhance biomethane production. The co-catalytic performance of Cr2O3, with 6% of melamine (precursor of C3N4), improved the photocatalytic degradation of 2-chlorophenol (k = 0.0156 min-1) under visible light, where up to 94% removal was achieved at optimum pH 5.0, pollutant concentration of 60 mg/L, and time duration of 180 min. On another hand, application of Cr2O3/C3N4 for photocatalytic pretreatment of sludge released the soluble substances in solution in which sCOD was increased from 431 mg/L to 3666 mg/L after 6 h and VS content decrease by only 9.1%, which indicated that the short time pretreatment could avoid the further mineralization of organic to complete degradation. Thereafter, anaerobic digestion of solubilized sludge was achieved after 30 days with production of 634 ml kg-1VS of methane and 46% of organic matter removal efficiency (OMRE), compared with 472 ml kg-1VS and 402 ml kg-1VS of methane, 35 and 31% of OMRE respectively in photolytic and raw sludge (control) reactors. These results can provide a useful base and reference for the multi applications of visible light Cr2O3/C3N4 photocatalyst in enhancement of degradation of toxic pollutant in wastewater and sludge stabilization with bioenergy production in practice.

Visible light photocatalytic disintegration of waste activated sludge for enhancing biogas production.

Biogas production using waste activated sludge (WAS) is one of the most demanding technologies for sludge treatment and generating energy in sustainable manner. The present study deals with the photocatalytic pretreatment of WAS using ZnO-ZnS@polyaniline (ZnO-ZnS@PANI) nanocomposite as means for increasing its degradability for improved biogas production by anaerobic digestion (AD). Photocatalysis accelerated the hydrolysis of WAS and increased the sCOD by 6.7 folds after 6 h and transform tCOD into bioavailable sCOD. After the AD of WAS, a removal of organic matter (60.6%) and tCOD (69.3%) was achieved in photocatalytic pretreated sludge. The biogas production was 1.6 folds higher in photocatalytic sludge with accumulative biogas up to 1645.1 ml L-1vs after 45 days compared with the raw sludge (1022.4 ml L-1VS). Moreover, the photocatalysis decrease the onset of methanogenesis from 25 to 12 days while achieve the maximum conversion rate of reducing sugars into organic acids at that time. These results suggested that photocatalysis is an efficient pretreatment method and ZnO-ZnS@PANI can degrade sludge efficiently for enhance biogas production in anaerobic digestion process.

Adsorption and anion exchange insight of indigo carmine onto CuAl-LDH/SWCNTs nanocomposite: kinetic, thermodynamic and isotherm analysis.

Two-dimensional layered materials are gaining much attention in the field of wastewater purification. Herein, we report the synthesis and characterization of an anion selective copper-aluminum-layered double hydroxide/single-walled carbon nanotubes (CuAl-LDH/SWCNTs) composite for the scavenging of organic dye indigo carmine (IC) from aqueous solution. A facile urea hydrolysis method was used for the controlled growth of the metal hydroxides over the SWCNTs. Structural characterization of the prepared materials was investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The obtained results revealed that the CuAl-LDH/SWCNTs composite has a higher potential for the removal of IC in comparison to CuAl-LDH and SWCNTs. The enhanced adsorption capacity of the composite revealed that deposition of CuAl-LDH over SWCNTs increases the active adsorption sites and promotes the interactions between the composite and IC dye via anion exchange, electrostatic, π-π, hydrogen bonding etc. Moreover, adsorption kinetics, isotherms, and thermodynamic studies have been also proposed to illustrate the mechanism of the IC adsorption onto the CuAl-LDH/SWCNTs composite. Thermodynamic parameters showed that the adsorption of IC dye onto the CuAl-LDH/SWCNTs composite was exothermic and spontaneous in nature. Intra-particle diffusion was determined to be the rate-limiting step and adsorption of IC followed the Langmuir isotherm model with the maximum monolayer adsorption capacity 294.117 mg g-1 at 20 °C. The results suggest that the CuAl-LDH/SWCNTs composite is a potential material for IC adsorption in aqueous solution.

Stabilized fabrication of anatase-TiO2/FeS2 (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue.

A novel visible light active TiO2/FeS2 semiconductor photocatalyst was synthesized by a simple wet chemical process. X-ray diffraction (XRD) was used to analyze the anatase TiO2 and pyrite structures in FeS2/TiO2 nanocrystals. Scanning electron microscopy (SEM) confirmed the spherical morphology of composite nanocrystals. X-ray photoelectron spectroscopy (XPS) identified the Fe2+, S1-, Ti4+, and O2- oxidation states of relevant species. Energy dispersive X-ray (EDX) analysis was performed for compositional analysis. The measured band gap of the TiO2/FeS2 nanocomposite system was 2.67 eV, which is smaller than un-doped TiO2 (3.10 eV) and larger than FeS2 (1.94 eV). The photocatalytic activity of TiO2/FeS2 was significantly higher than pure FeS2 for degrading methylene blue (MB) under solar light irradiation due to the increase in visible light absorption, reduction in band gap energy, and better election-hole pair separation. The photocatalytic degradation of MB was investigated under the influence of solution pH, dye concentrations, and varied catalyst dosage. The optimum degradation (100%) of MB was observed in 180 min and the photocatalysis of MB reduced as the dye concentrations in the solution increased from 15 to 75 mg L-1. These results prove that the TiO2/FeS2 nanocomposite has the stability, recycling, and adaptability for its practical application as a visible light photocatalyst for wastewater treatment. TiO2/FeS2 showed increased degradation of the organic pollutant; which is confirmed by the increased rate of chemical reaction following pseudo first-order reaction kinetics with the highest rate constant value of 0.0408 m-1 having highest R 2 value of 0.9981.

Untapped conversion of plastic waste char into carbon-metal LDOs for the adsorption of Congo red.

A low-cost novel carbon-metal double layered oxides (C/MnCuAl-LDOs) nano-adsorbent was synthesized by co-precipitation, for the adsorption of Congo red (CR), using modified carbon derived from pyrolysis of polystyrene (PS) plastic waste. The synthesized C/MnCuAl-LDOs has a crystalline structure with a high surface area of 60.43m2/g and pore size of 99.85Å. Adsorption of CR using all prepared adsorbents from aqueous solution under equilibrium and kinetic conditions were evaluated against different values of the pH (4-10), initial CR concentrations (25-250mg/g), contact time (0-310min) and temperature (30-50°C). The obtained results revealed that C/MnCuAl-LDOs showed maximum adsorption capacity for CR among all the used adsorbents. The optimum equilibrium time was 180min, whereas acidic medium (pH 4.5) favored the maximum adsorption of CR up to 317.2mg/g on C/MnCuAl-LDOs. The adsorption kinetics followed the pseudo-second-order model, whereas Freundlich adsorption isotherm fitted best to obtained data in comparison to Langmuir adsorption isotherm. The results suggested that C/MnCuAl-LDOs is an efficient material for the removal of organic pollutants from the wastewater.

Optimization of food waste compost with the use of biochar.

This paper aims to examine the influence of biochar produced from lawn waste in accelerating the degradation and mineralization rates of food waste compost. Biochar produced at two different temperatures (350 and 450 °C) was applied at the rates 10 and 15% (w/w) of the total waste to an in-vessel compost bioreactor for evaluating its effects on food waste compost. The quality of compost was assessed against stabilization indices such as moisture contents (MC), electrical conductivity (EC), organic matters (OM) degradation, change in total carbon (TC) and mineral nitrogen contents such as ammonium (NH4+) and nitrate (NO3-). The use of biochar significantly improved the composting process and physiochemical properties of the final compost. Results showed that in comparison to control trial, biochar amended compost mixtures rapidly achieved the thermophilic temperature, increased the OM degradation by 14.4-15.3%, concentration of NH4+ by 37.8-45.6% and NO3- by 50-62%. The most prominent effects in term of achieving rapid thermophilic temperature and a higher concentration of NH4+ and NO3- were observed at 15% (w/w) biochar. According to compost quality standard of United States (US), California, Germany, and Austria, the compost stability as a result of biochar addition was achieved in 50-60 days. Nonetheless, the biochar produced at 450 °C had similar effects as to biochar produced at 350 °C for most of the compost parameters. Therefore, it is recommended to produce biochar at 350 °C to reduce the energy requirements for resource recovery of biomass and should be added at a concentration of 15% (w/w) to the compost bioreactor for achieving a stable compost.

Oxidized g-C3N4/polyaniline nanofiber composite for the selective removal of hexavalent chromium.

Nanomaterials with selective adsorption properties are in demand for environmental applications. Herein, acid etching and oxidative decomposition of melon units of graphitic carbon nitride (g-C3N4) was performed to obtain the oxidized graphitic carbon nitride (Ox-g-C3N4) nanosheets. Ox- g-C3N4 nanosheets were further decorated on the polyaniline nanofiber (Ox-g-C3N4/Pani-NF). Ox-g-C3N4/Pani-NF was well characterized and further applied for a selective removal of hexavalent chromium (Cr(VI)) form aqueous solution. The zeta potential analysis indicate that the surface of Ox-g-C3N4/Pani-NF was positively charged which could be beneficial to bind anionic Cr(VI) ions electrostatically. In addition, nitrogen and oxygen containing functional groups exist on the Ox-g-C3N4/Pani-NF were mainly responsible for adsorption of Cr(VI) ions from aqueous solution. Moreover, the adsorption of Cr(VI) ions was also dependent on solution pH, reaction temperature and initial concentration of Cr(VI) ions. The maximum monolayer adsorption capacity of Ox-g-C3N4/Pani-NF for Cr(VI), calculated from Langmuir isotherm was 178.57 mg/g at pH = 2 and 30 °C. The activation energy (Ea = -20.66 kJ/mol) and the enthalpy change (ΔH° = -22.055 kJ/mol) validate the role of physical forces in adsorption of Cr(VI). These results demonstrate that Ox-g-C3N4/Pani-NF can be used as a potential adsorbent for environmental remediation applications.

Plastic waste to liquid oil through catalytic pyrolysis using natural and synthetic zeolite catalysts.

This study aims to examine the catalytic pyrolysis of various plastic wastes in the presence of natural and synthetic zeolite catalysts. A small pilot scale reactor was commissioned to carry out the catalytic pyrolysis of polystyrene (PS), polypropylene (PP), polyethylene (PE) and their mixtures in different ratios at 450°C and 75min. PS plastic waste resulted in the highest liquid oil yield of 54% using natural zeolite and 50% using synthetic zeolite catalysts. Mixing of PS with other plastic wastes lowered the liquid oil yield whereas all mixtures of PP and PE resulted in higher liquid oil yield than the individual plastic feedstocks using both catalysts. The GC-MS analysis revealed that the pyrolysis liquid oils from all samples mainly consisted of aromatic hydrocarbons with a few aliphatic hydrocarbon compounds. The types and amounts of different compounds present in liquid oils vary with some common compounds such as styrene, ethylbenzene, benzene, azulene, naphthalene, and toluene. The FT-IR data also confirmed that liquid oil contained mostly aromatic compounds with some alkanes, alkenes and small amounts of phenol group. The produced liquid oils have high heating values (HHV) of 40.2-45MJ/kg, which are similar to conventional diesel. The liquid oil has potential to be used as an alternative source of energy or fuel production.