Pseudo-first Order Reaction Research Articles

Green Synthesis of Mixed ZnO-SnO2 Nanoparticles for Solar-Assisted Degradation of Synthetic Dyes

In this work, ZnO, SnO2, and their mixed ZnO-SnO2(25%) nanoparticles (NPs) were successfully green synthesized in a straightforward manner with a low-cost and environmentally friendly approach using a banana peel extract. The synthesized nanophotocatalysts were characterized using various techniques including FTIR, XRD, UV-Vis, TEM, SEM, BET, PL, EDS, and TGA. The characterization results showed that the ZnO and SnO2 powders were crystallized in a hexagonal wurtzite and rutile-type tetragonal structures, respectively, and their mixed ZnO-SnO2(25%) NPs contain both structures. Also, it was found that the addition of SnO2 into the ZnO structure reduces the PL intensity of the latter, confirming better separation of electron/hole pairs. The average particle size of a ZnO-SnO2(25%) NP photocatalyst was found to be 7.23 nm. The cationic dyes methylene blue (MB) and crystal violet (CV) as well as the anionic dyes naphthol blue black (NBB) and Coomassie brilliant blue R 250 (CBB) were employed as model dyes to assess the dye removal efficiencies of the biosynthesized nanophotocatalysts under sunlight. In all cases, the mixed ZnO-SnO2(25%) NP photocatalyst showed much better photocatalytic activity than individual photocatalysts. The degradation percent of dyes using ZnO-SnO2(25%) NPs ranged between 92.2% and 98%. The efficient photocatalytic activity of ZnO-SnO2(25%) NPs is attributed to the effective charge separation and reduced electron/hole recombination rate. The kinetic study results conformed to a pseudo first-order reaction rationalized in terms of the Langmuir–Hinshelwood model. Furthermore, the results showed that the ZnO-SnO2(25%) NP photocatalyst is highly stable and could be recycled several times without a noticeable reduction in its catalytic activity towards dye removal.

Cocos Nucifera’s lignin mediated silver nanoparticle and their photocatalytic activity

As an alternative to physical and chemical synthesis, green synthesis of metal nanoparticles provides a non-toxic way to create nanoparticles. The goal of this study is to create silver nanoparticles (AgNPs) by combining lignin as a reducing agent, which is extracted from Cocos Nucifera (coconut) husks and screened their photocatalytic activity for the removal of methylene blue (MB) dye. UV–Visible and FTIR spectroscopy were used to analyse the synthesised AgNPs, while TEM and FESEM-EDX were used to screen the surface morphology. TEM and SEM evidenced that the AgNPs resultant is sphere-shaped, with a particle size in the range of 20–40 nm. The photocatalytic activity of the AgNPs alongside NaBH4 to degrade MB was then evaluated. According to the findings, the AgNPs degraded the MB by 90.60 % in just 30 min. The degradation pathway obeyed pseudo-first order reaction kinetics with k = 0.0678 min−1.

A Spectroscopic Approach on Permanganate Oxidation of 1-[(4-Chlorophenyl)methyl]piperidin-4-amine in Presence of Ruthenium(III) Catalyst with DFT Analysis on Reaction Mechanism Pathway

The kinetic oxidation of 1-[(4-chlorophenyl)methyl]piperidin-4-amine (CMP) using alkaline potassium permanganate in presence of Ru(III) as catalyst was conducted spectrophotometrically at 303 K. The Pseudo first-order reaction was maintained with regard to oxidant and substrate during the reaction at an ionic strength of 0.01 mol dm-3. The first-order kinetics has been depicted with respect to catalyst Ru(III) chloride and less than unit order with substrate and medium. For the slow step, different activation parameters including ΔH# (kJ mol-1), Ea (kJ mol-1), ΔG# (kJ mol-1) and ΔS# (J K-1 mol-1) were calculated. The effect of temperature, variation of substrate concentration, oxidant, ionic strength were studied. The stoichiometry ratio of the reaction to the substrate and oxidizing agent was found to be 1:4. The products of reaction were isolated and identified as chlorobenzene and L-alanine, N-(2-aminomethylethyl)-carboxylic acid by LC-MS spectra, a suitable mechanism has been proposed and the rate laws are derived. The frontier molecular orbital (FMO) and frontier electron density (FED) of piperidiamine and the oxidative products were studied using density functional theory (DFT). The results of the theoretical calculations supported the suggested reaction pathways.

Insights into the electron transfer mechanisms of peroxydisulfate activation by modified metal-free acetylene black for degradation of sulfisoxazole

Herein, a modified metal-free acetylene black (MMF-AB) catalyst was synthesized by a simple solvothermal-calcination method and designed successfully to activate peroxodisulfate (PDS) for the degradation of sulfisoxazole (SIZ). Due to the doping of N, S and O metal-free elements, the modified catalyst showed excellent catalytic performance with 100% SIZ removal within 30 min. Pseudo first-order reaction rate constants (evaluating catalytic efficiencies and activity) of MMF-AB (kobs = 0.105 min−1) was 3 times higher than pure-AB (kobs = 0.029 min−1). Interestingly, it was demonstrated that the reaction system is based on the transfer of electrons from SIZ to PDS to realize an electron-transfer-based mechanism by the evidence of premixing, electron paramagnetic resonance (EPR) spectroscopy, salt-bridge experiments and electrochemical analyses. The introduction of recyclable filtration device solved the secondary pollution caused by the dispersion of the powdered catalyst in the treated water, which further proved the practicality and superiority of the MMF-AB catalyst.

Characterization of Green synthesised Iron nanoparticles and application of synthesised Iron nanoparticles as an effective catalyst for the removal of Carcinogenic metals in aqueous solution

The heavy metals such as chromium (Cr), lead (Pb) and cadmium (Cd) are considered as serious toxicants and act as carcinogenic agents that cause serious cancers to humans. The use of these heavy metals drastically increased in various industrial applications and subsequently increased the risk of contamination of these heavy metals in soil, water etc. To minimize the negative effects of these heavy metals, there is a need to reduce these heavy metals concentrations in environment samples. Hence this study focused to fabricate iron nanoparticles using Diospyros chloroxylon (Roxb.) for the removal of carcinogenic metals in water. The crystal structure, size and morphology of the nanoaprticles were evaluated and it was found that the particles were of rod shape with smooth surface and rhombohedral phase structure with an average particle size of 24 nm that contains 71.91 % of elemental iron. The heavy metal sorption experiments was conducted using selected concentration of heavy metal solution at various pH ranges, time and agitation rate. The maximum adsorption removal was 95.36 %, 98.42 % and 92.80 % within 120 min equilibrium time for Cr, Pb and Cd respectively suggesting that the nanoparticles possess high adsorption efficiency. The adsorption process follows pseudo-first order reaction kinetics with correlation coefficient of 0.978, 0.994 and 0.994 with rate constant (K) of 0.140, 0.280 and 0.108 respectively for Cr, Pb and Cd. The results suggest that the synthesized iron nanoparticles were biocompatible, stable and reusable that can be effectively utilized as promising agents for the removal of carcinogenic heavy metals in polluted water.

Hydroxyl radical-driven transformations of bisphenol A and 2,4-dinitroanisole: Experimental and computational analysis.

This study used experimental and computational analysis to investigate the advanced oxidation of bisphenol A (BPA) and 2,4-dinitroanisole (DNAN). The pseudo first-order reaction rate constants depended on the molar peroxide ratio and were between 0.13 and 0.28 min-1 for BPA and between 0.018 and 0.032 min-1 for DNAN. The kinetic differences appear to be due in part to the energy requirements for oxidation, which depended on the reaction mechanism but were typically lower for BPA than they were for DNAN. Density functional theory (DFT) was used to develop transformation pathways that included experimentally-detected byproducts. The most energetically favored pathway for BPA oxidation begins with the formation of hydroxylated derivatives, while for DNAN, the most energetically favorable degradation pathway begins with the substitution of the methoxy group. Overall, these findings demonstrate the power of combining experimental and computational tools to reveal transformation mechanisms during water treatment. PRACTITIONER POINTS: Advanced oxidation transformations for two emerging water pollutants, bisphenol A and dinitroanisole, was investigated. The observed reaction kinetics depended on molar peroxide ratio in a manner that is in keeping with previous findings. Density functional theory-based analysis revealed reaction energy requirements and degradation pathways.

Mass transfer and reaction mechanism of CO2 capture into a novel amino acid ionic liquid phase-change absorbent

In order to overcome high heat duty and poor regeneration efficiency of existing chemical absorbent, a novel aqueous amino acid ionic liquids (AAILs) phase change absorbent with tetraethylenepentamine (TEPA) as cation, L-proline (L-Pro) as anion and N-propanol (NPA) as phase separator was proposed in this study. [TEPAH][Pro]/NPA/H2O owned the maximum absorption loading of 2.01 mol CO2·mol absorbent−1, and the rich phase viscosity was only 8.06 mPa·s. Moreover, its desorption efficiency was 84.4% while the 5th cyclic loading kept above 1.61 mol CO2·mol absorbent−1. With the presence of NPA, the rich phase only accounted for 41% of the total volume while it contained 99.3% of CO2 products. The heat duty was only 2.39 GJ·t CO2-1, which was 37% lower than that of 30 wt% ethanolamine (MEA) aqueous solution. Meanwhile, the reaction mechanism and product distribution were revealed by 13C NMR and the mass transfer kinetics was investigated using the wetted wall column. The products in the rich phase mainly consisted of carbamate, hydrogen carbonate, propyl carbonate and water while the main component of the lean phase was NPA. The reaction followed a fast pseudo-first order reaction. At 313.15 K, the rate constant of fresh absorbent was 51346 s−1, which showed a decreasing trend with the increase of absorption loading at 313.15 K. The second order reaction rate was calculated by: k2 = 9.88 × 109exp(-3591.2/T), where the reaction activation energy was only 29.86 kJ·mol−1.

Novel dragon fruit peel ash-derived solid catalyst for biodiesel production and PET waste recycling

The present protocol demonstrates the development of an affordable methodology for synthesizing biodiesel and depolymerizing PET waste using dragon fruit (Hylocereus costaricensis or Hylocereus polyrhizus) peel ash derived solid catalyst. The reported catalytic process yielded 99 % biodiesel at room temperature in 5 h with 8 wt% catalyst amounts and 12 M equivalents of methanol, while requiring just 20 min of run time at an elevated temperature (65 °C). The reaction was found to be endothermic pseudo-first order reaction having activation energy of 56.36 kJ mol−1. Meanwhile, PET waste was depolymerized to bis(2-hydroxyethyl) terephthalate (BHET) in 1.5 h at 190 °C with 16 equivalents of ethylene glycol and 4 wt% of the catalyst, giving 84 % of the desired monomer. The developed catalyst and the resultant products are thoroughly characterized using a variety of techniques to determine the catalyst's chemical composition and to confirm the formation of the desired products.

Iron electrocoagulation activated peracetic acid for efficient degradation of sulfamethoxazole

Activation of peracetic acid (PAA) by Fe species is the attractive advanced oxidation processes for the removal of antibiotics. However, achieving optimal performance in many of these processes often requires acidic pH conditions, which impedes practical application. In this study, an iron electrocoagulation (EC) system was devised to for activate PAA and oxidate sulfamethoxazole (SMX). Under optimal conditions, the degradation of SMX by the EC/PAA system reached 96.2% within 15 min, with a pseudo-first order reaction constant of 0.241 min−1, but only consuming 0.044 kW·h/m3. Interestingly, the EC/PAA system showed a high buffering capacity in the initial pH range of 4–8 to maintain the final pH of around 7. The quenching experiments revealed both free radical and non-free radical pathways involved in the oxidation of SMX in the EC/PAA system. Specifically, the active species, including •OH, organic radicals (CH3COO• and CH3COOO•) and 1O2, contribute 86.77%, 5.53% and 7.70%, respectively. These findings suggest that the EC/PAA system has unique advantages and potential for the degradation of antibiotic organics such as SMX in aquatic environments due to its strong oxidative capacity, wide pH range and high buffering capacity.

Functional mimic for catechol oxidase and phenoxazinone synthase: Structural, spectral, electrochemical and catalytic properties of mononuclear copper(II) complex

A promising bioinspired metallocatalyst [Cu(L1)2(L2)] (L1 = P-hydroxybenzoic acid, L2 = N1,N1-dimethylpropane-1,3-diamine) has been produced and characterized in accordance with reports. In the octahedron arrangement around the copper ion, the elongation along one axial direction and one equatorial direction results in a distorted geometry Molecular assembly shows both inter and intra molecular H-bonding along with CH---π interactions evident from the Hirhsfeld surface analysis. The fingerprint plot discloses the relative contribution of percentage of intermolecular contacts (H⋯H, C⋯H and O⋯H) in the complex. The EPR, CV, and UV analyses collectively support that the complex exhibits such activity via oxygen dependant enzymatic radical pathway. Furthermore, these activities are observed under fully aerobic conditions in which 3,5-di-tert-butylcatechol (3,5-DTBC) and 2-amino phenol (2-AP) are used as model substrates. Michaelis-Menten analysis derived from the pseudo first-order reaction kinetics established that this complex shows extremely high catalytic activity towards 3,5- DTBC and 2-AP (Kcat 1.729 × 105 h−1 and 0.260 × 105 h−1). The suggested mechanism has been supported by UV spectra data in which formation of hydrogen peroxide by observing the appearance of spectral band at λmax 353 nm indicates the active participation of molecular oxygen in the catalytic process.

Optimization of Green Synthesis Parameters of Silver Nanoparticles with Factorial Design for Dye Removal

In this study production of silver nanoparticles (AgNPs) from collard greens were optimized by the design of experiments (DOE). A 24 full factorial design was employed to evaluate the effects on two responses. The optimized values for AgNP production were 1:7 leaf to water, 1:4 extract to AgNO3, 5 molar AgNO3, and a leaf size of <1 mm. For dye removal efficiency, the optimized values were changed to 1:15 of leaf to water and 1:10 of extract to AgNO3, while the other two parameters remained the same. SEM (scanning electron microscopy) showed that optimizing the process for dye removal led to smaller AgNP production with increased surface area, resulting in higher absorbency. ANOVA (analysis of variance) tables were used to interpret each parameter's main and effects on interaction. Additionally, reaction rate kinetics were estimated, and dye removal showed a slightly higher R-square of pseudo second-order than NP production, which fits the pseudo first-order reaction model.

Calcium oxide nanoparticles: Biosynthesis, characterization and photocatalytic activity for application in yellow tartrazine dye removal

Dyes are substances that have a high polluting potential, due to their low biodegradability and chemical stability, causing serious environmental damage when disposed of incorrectly. Yellow tartrazine (YT) dye as an environmental liability requires attention, since it causes toxic effects in fish (Danio rerio) with a potential allergic effect in humans. In this context, the present study aims to synthesize and characterize calcium oxide nanoparticles (CaO-NPs) to evaluate the photocatalytic activity for the YT photodegradation under visible irradiation. CaO-NPs were synthesized by the biosynthesis method from golden linseed (Linum usitatissimum L.) extract. Central Composite Rotational Design (CCRD 23) was used to determine the ideal condition for the photocatalytic tests. X-ray diffraction (XRD), zeta potential (ZP), physical adsorption of N2, zero charge point (pHzcp), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy by Energy Dispersive Spectroscopy (SEM-EDS), Diffuse Reflectance Spectroscopy (DRS) and Field Emission Gun – Scanning Electron Microscope (FEG-SEM) were used to the CaO-NPs characterization. Thus, CaO-NPs presented SBET = 14±0.02 m2g−1, Dp = 20.9±0.02 nm and Vp = 0.054±0.004 cm3g−1, characteristic of a mesoporous material. ATR-FTIR spectrum showed characteristic stretches of specific functional groups (–CH, –CO, C = C, Ca-O, –OH) from plant extract and metallic precursor. CaO-NPs showed pHZCP equal to 7.74, positive surface charge (+12.7 mV) and bang gap energy of 2.61 eV. FEG-SEM micrographs showed that has a small agglomeration with defined morphology, but with irregular particle size (around 48 nm), and SEM-EDS micrographs showed an elemental composition (in weight) of the 50.24% oxygen, 3.32% magnesium, 2.29% iron, 10.44% calcium, 14.07% silicon, 3.33% aluminum and 0.63% potassium. Regarding CCRD 23, the ideal condition was the pH = 7.0, [CaO-NPs] = 1.2 g/L and [YT] = 20 mg/L, with 76.2% of photodegradation and a pseudo first-order reaction specific reaction rate k = 0.089 min−1. After V cycles of CaO-NPs recycling, there was a decrease of around 22.83%, indicating a saturation of the active sites available in the nanocatalyst Therefore, CaO-NPs showed potential application for TY photodegradation to be used in wastewater treatment being an alternative nanocatalyst, meeting nanotechnology and sustainable development.

Enhanced sonophotocatalytic degradation of amoxicillin antibiotics using Fe3O4@SiO2/PAEDTC surrounded by MIL-101(Fe) in aquatic environment under the COVID-19 pandemic

In the conditions of corona disease, the need for antibiotics in the world has quadrupled, so it is required to remove their residues from the environment. A core–shell metal–organic framework (MOF) composed of Fe3O4, SiO2, and MIL-101 was synthesized by hydrothermal method and used as a sonophotocatalyst for the amoxicillin (AMX) degradation from aqueous solution. The features of the new MOF were determined by SEM, TEM, XRD, FTIR, and BET techniques. The specific area of core–shell magnetic particles was 992 m2/g, which was indicative of its usability to adsorb pollutants and photons. Complete degradation of AMX was achieved by sonophotocatalysis process based on prepared nanocomposite at pH of 5, UV intensity of 36 W, AMX concentration of 50 mg/L, US frequency of 36 kHz, and time of 25 min. Kinetic study with pseudo-first order reaction for the decomposition of AMX showed the order of kinetic constant rate as Ksonophotocatalytic > Kphotocatalytic > Ksonocatalytic > Kadsorption. Hydroxyl radicals (•OH) and holes (h+) were respectively determined as the main species in the decomposition of AMX by performing quenching experiments. Less than an 8% reduction in AMX degradation rate was observed by the sonophotocatalytic process in the presence of prepared nanocomposite during six consecutive reaction cycles. Removal rates of TOC > 77% and BOD5/COD ratio > 0.4 showed that AMX was converted to CO2, H2O, and simple degradable compounds during the sonophotocatalysis process. A toxicity study with the microbial culture of Escherichia coli (E. coli) demonstrated a lower inhibition rate in the sonophotocatalytic process compared to photolysis and photocatalytic processes. All the laboratory results proved that the Fe3O4@SiO2@MIL-101(Fe) is an encouraging candidate for AMX degradation to preserve the ecosystem.

Nitrogen–Fluorine co-doped TiO2/SiO2 nanoparticles for the photocatalytic degradation of acrylonitrile: Deactivation and regeneration

In this study, we investigated the deactivation kinetics and mechanism of N–F–TiO2/SiO2 nanopowder as a model photocatalyst for the purpose of facilitating the photocatalytic degradation of acrylonitrile (AN) in aqueous environment. Prior research has already displayed the proficient degradation of AN through the utilization of N–F–TiO2/SiO2 catalysts, revealing a degradation efficiency of 81.2% within a span of 6 min at an initial AN concentration of 10 mg/L. Multiple variables including the initial AN concentration, illumination intensity, and initial pH value were extensively analyzed during the degradation process. The kinetics of photocatalytic degradation of AN, facilitated by the N–F–TiO2/SiO2 photocatalyst, were modeled by fitting the pseudo first-order reaction kinetics to each individual factor. Furthermore, the adverse effect of catalyst poisoning during the photocatalytic breakdown of AN using the N–F–TiO2/SiO2 photocatalyst was analyzed through a range of different techniques including SEM, XPS, BET, XRD, TG, and NH3-TPD. The incorporation of findings from these diverse techniques revealed that, the primary factors contributing to the photocatalyst's poisoning were as follows: (i) During the degradation process, the build-up of intermediate molecules on active sites hindered their functionality, leading to a decrease in the efficiency of the photocatalytic reaction, (ii) Carbonaceous deposits formed when the catalyst's pore structure was obstructed by pollutants or intermediate products that had not undergone timely photocatalytic breakdown and (iii) The persistent erosion of active sites due to hydraulic forces resulted in inadequate performance of the N–F–TiO2/SiO2 photocatalyst in aqueous solutions. A comprehensive analysis of the deactivation kinetics was conducted, deciding in the formulation of a detailed poisoning mechanism for the N–F–TiO2/SiO2 photocatalyst. Additionally, we explored the catalysts regeneration, involving thermal treatment, ultrasonic irradiation, and catalyst reloading. This study not only advances our insight into the waning performance of catalysts in aqueous media but also establishes a conceptual framework for extrapolating analogous deactivation dynamics in other catalysts, grounded in precedent experimental knowledge. This research contributes to the development of a deactivation model for catalysts in the aqueous environment, based on existing experimental research, providing a theoretical framework for understanding the deactivation process of photocatalysts.

Phosphorus-modified copper ferrite (P–CuFe2O4) nanoparticles for photocatalytic ozonation of lomefloxacin

Phosphorus-modified copper ferrite (P–CuFe2O4) nanoparticles were prepared by a simple sol-gel auto-combustion process and used for the photocatalytic ozonation of lomefloxacin (LOM). The morphology, crystallinity, and structure of the synthesized CuFe2O4 and P–CuFe2O4 nanoparticles were investigated using various techniques. The high-performance liquid chromatography (HPLC) analysis revealed that the degradation of LOM achieved a 99% reduction after a duration of 90 min in the photocatalytic ozonation system. In accordance with the charge-to-mass ratio, four intermediates were proposed with the help of their fragments obtained in LC–MS/MS. The degradation kinetics of lomefloxacin followed a pseudo-first order reaction, and the degradation mechanism was proposed based on the results. P0.035Cu0.965Fe2O4 showed the highest total organic carbon (TOC) removal with 20.15% in 90 min, highest specific surface area and the highest fluoride and ammonium production using the ion chromatography (IC). The experimental results obtained from the electron paramagnetic resonance (EPR) analysis indicated that the modified P–CuFe2O4 samples exhibited significantly elevated levels of superoxide (.O2−) production compared to the CuFe2O4 samples. The findings of this study demonstrate that the introduction of phosphorus modification into the copper ferrite photocatalyst led to an augmentation of both the specific surface area and the total pore volume. Furthermore, the incorporation of phosphorus served to promote the efficient separation of electron-hole pairs by effectively trapping electrons in the conduction band, hence enhancing the degradation efficiency.

Fabrication and kinetic evaluation of dye adsorption capability of metal Oxide@RGO nanocomposites integrated cellulose triacetate membranes

Reduced Graphene Oxide (RGO) and its derivatives exhibit remarkable removal abilities of water pollutants that can further be enhanced by the incorporation of the metallic nanoparticles. However, the challenging collection of GO sheets and fabrication method of RGO-based materials during the adsorption process, constraint their practical uses. The integration of the RGO-based materials on the polymeric matrix offers a solution to this problem. In current study, three types of metal oxide@RGO nanocomposites integrated Cellulose Triacetate (CTA) membranes with adsorption abilities were prepared by a facile blending and phase inversion technique. The fabricated membranes exhibited selective adsorption for azo dyes at room temperature. The adsorption parameters depicted the Langmuir and pseudo-first order kinetic order reaction. It was found that the adsorption process was directed by the inter-particle diffusion. These membranes were found to be effective against varying range of the pollutants and can be fabricated by the facile techniques.

Comparison of kinetic study of the adsorption of bromothymol blue on activated Attapulgite clay and commercial activated carbon

This work is included studying the removal efficiency method of bromothymole blue (BTB) from industrial waste water by using thermally activated Attapulgite clay (ATC) and by activated carbon (AC) as adsorbent when applying adsorption technology. The most efficient dose obtained for the removal of BTB by AC and ATC is then using 20 mL of dye solution with 3*10-4 M concentration are 0.03 and 0.1 g respectively. The use of AC required 0.03g of AC to give % ads 95.97 while the use of o.1 g of ATC gave % ads. 91.71, The results gave a preference of the clay ATC to be used as a cheap and efficient adsorbent. Comparison of the adsorption efficiency of the Attapulgite clay with commercial activated carbon where carried out. The optimal conditions of the adsorption systems under study such as effect of dose, initial concentration, and temperature were investigated. Two isotherm models, Langmuir and Freundlich were fitted to the experimental data of adsorption. The thermodynamic Functions of the studied systems (∆Ho, ∆G°, ∆S°) were estimated. The results of the thermodynamic study showed that the forces controlling the adsorption process of the systems under consideration are physical in nature. The adsorption process is exothermic, occur spontaneously in the direction of connecting the dye to the clay surface, and forming less random system. The research also included achieving kinetic study by application of the pseudo first-order and pseudo second-order reaction models on the experimental data of the studied system, this indicted by the value of R2 (0.999) and the agreement between the experimental and calculated ( qe ) . The second order equation were better fitted to the experimental data of the system under consideration. In addition, the matching of the calculated qe value (34.843 mg/g) with the practical (33.821 mg/g) one sustain this results. The application of the intra-particle diffusion method showed that, the diffusion process of the adsorbed molecules into the pores present on the adsorbent surface is not the only mechanism driving the adsorption process in the studied reaction Kdiff.(mg.g‾¹.min‾½) = 0.893, R2 = 0.943.

Behaviour Study of Four Insecticides using different Mathematical Modeling

The adsorption, distribution coefficient, Langmuir and Freundlich models and the mathematical evaluation of pesticides have become more interesting from an environmental point of view. The outcomes revealed that indoxacarb, imidacloprid, and lambda-cyhalothrin are subjected to the Pseudo-first order reaction (PFO). The rate of degradation was reached, into 0.01, 0.07, and 0.04 a minute respectively. While chlorantraniliprole reached 0.00002 a minute. This indicates that these insecticides are decreasing in their concentrations depending only on the time. Hence, the time required to decrease 50% of each insecticide (DT50) was various periods. The DT50 for indoxacarb, imidacloprid, and lambda-cyhalothrin, and chlorantraniliprole 3.2, 1.9, 10.1, and 2.3 days respectively. The distribution Coefficient Kd as well scored (5.25, 1.30, 0.562, and 0.639) mL g-1 respectively. This indicated that indoxacarb, imidacloprid has a mobility behaviour, while the lambda-cyhalothrin and chlorantraniliprole are less mobile in the soil. In terms of Freundlich model (aF), chlorantraniliprole 2.82 and lambda-cyhalothrin 2.75 are more fit than indoxacarb 0.013 L g-1 and imidacloprid 0.249 L g-1 subjected to the Langmuir model (KL).

Effective photodegradation of organic water pollutants by the facile synthesis of Ag2O nanoparticles

In this study, Ag2O nanoparticles were synthesized using a low-cost precipitation method. The synthesized nanomaterials are characterized by XRD, FTIR, XPS, Photoluminescence, and EDX. The shape and excellent size of incorporated Ag2O nanoparticles were exhibited utilizing SEM and XRD. XRD patterns of precipitated Ag2O powders indicated a cubic structure with crystallite diameters of 18.5 nm, respectively. The photocatalytic degradation of Rhodamine-B (Rh-B) gathered from the dyeing industry was used to examine the Ag2O nanoparticles. The photocatalytic activity of Rh-B degradation in an aqueous solution was also studied; this process resulted in a 76 % reduction of the dye in 60 minutes when exposed to UV-visible light. In the instance of pseudo first-order reaction kinetics, this corresponds to rate constants of 0.99804 min−1. As a result, precipitation was used to increase the photocatalytic activity of Ag2O nanostructures. The findings provide a pathway to developing advanced photocatalysts that may effectively remove organic contaminants in water using just visible light.

Cobalt-loaded carbon nanotubes boosted aerobic ciprofloxacin transformation driven by sulfide: A comprehensive mechanism investigation

Sulfide oxidation under aerobic conditions can produce active oxygen for the transformation of organic pollutants in aquatic environments. However, the catalytic performance of transition metal-supported carbon material on this process is poor understood. This study found that Co-loaded carbon nanotubes (CNTs) was able to realize the efficient aerobic transformation of antibiotic ciprofloxacin (CIP) by sulfide, with the pseudo-first order reaction rate constant improved from 0.013 h−1 without catalyst to 0.44–0.71 h−1 with 100 mg/L Co-loaded CNTs. Singlet oxygen (1O2) was the main active specie playing key roles in the process of CIP aerobic transformation with presence of Co-loaded CNTs. Mechanism studies indicated that the excellent electron transfer ability of Co-loaded CNTs might play an important role to promote the electron transfer and facilitate the formation of intermediate H2O2 and 1O2. Additionally, the Co-loaded CNTs/sulfide system effectively reduced the acute toxicity of organic pollutant, and Co-loaded CNTs showed remarkable cycling stability and negligible leaching. This study gives a better understanding for the Co-loaded CNTs mediated aerobic antibiotics transformation by sulfide, and provide a reference for the application of Co-loaded carbon materials on organics aerobic transformation by sulfide.