Fine Chemical Engineering

Study on Glyphosate Adsorption onto ZIF-8 Modified with Fe₃O₄ Nanoparticles

Immanuel Joseph Ondang — 2024-05-14

Glyphosate (GLYPi) is an organophosphorus herbicide that behaves as an anionic substance in the aqueous phase. Even though it is stated as safe and non-toxic, the widespread use of GLYPi has raised environmental issues that need attention. This work used the positively charged metal-organic framework (MOF) of ZIF-8 to remove GLYPi via adsorption. Fe₃O₄ particles were hybridized with ZIF-8 to obtain Fe₃O₄@ZIF-8 via an in-situ deposition strategy to enhance the adsorption capacity toward GLYPi. The composite material (Fe₃O₄@ZIF-8) was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction, revealing rhombic dodecahedron-shaped particles and oxygen-rich functional groups. The adsorption results show that there is a synergistic effect of adding Fe₃O₄ to ZIF-8 in increasing the rate and capacity of adsorption on GLYPi, that is 0.0012 g/mg·min (Pseudo-second-order) and 73.57 mg/g (Langmuir), respectively, on pH 7 and 50 °C. GLYPi adsorption by Fe₃O₄@ZIF-8 was not influenced by coexisting anions (e.g., Cl^-, NO₃^-, SO₄^2-, and HCO₃^-). The reusability study showed that the adsorption efficiency of GLYPi by Fe₃O₄@ZIF-8 decreased significantly after the first cycle, which should be considered a future challenge for further studies. The adsorption mechanisms of GLYPi by Fe₃O₄@ZIF-8 involve electrostatic interaction and pore-filling. The results indicate that Fe₃O₄@ZIF-8 is a promising candidate for removing organophosphate compounds, which could be an excellent strategy for environmental protection.

Thermal Decomposition of Pure Waste and Binary Mixtures

Thalyne de Almeida Ferreira Rocha — 2024-06-06

In this study, the thermal decomposition of pure organic residues - coffee grounds, sugarcane bagasse and orange juice residues - and their binary mixtures with coffee grounds were analyzed. The results of thermogravimetric analyses at 10 °C/min under an oxidizing atmosphere showed that sugarcane bagasse and coffee grounds had individually higher reaction rates in the devolatilization zone, while orange juice residues burned more quickly in the combustion zone. There were significant mass interactions between the coffee grounds and orange juice residues in the binary mixtures, which led to higher reaction rates in the combustion of the mixture than in the pure residues. In the mixture of coffee grounds and sugarcane bagasse, there were no significant mass interactions. These encouraging findings can optimize the generation of bioenergy from these wastes and their mixtures, therefore, one must understand the different interactions during thermal decomposition to then develop sustainable strategies for utilizing biomass.

Efficiently Controlled Callosobruchus maculatus (F.) (Fam. Bruchidae) by Ultraviolet Ray or Microwave Energy in Conjugation with Pirimiphos-Methyl

Eslam A. Negm — 2024-04-23

This study aimed to explore novel approaches for effectively managing Callosobruchus maculatus while ensuring minimal impact on human health and the environment. The investigation involved exposing the insects to ultraviolet rays (254 nm) for 24 hours, which did not directly cause mortality in adult C. maculatus but led to a significant reduction in their progeny by 10%. The reduction in progeny further increased when insects were pre-exposed to a sublethal dose of actellic at LC₂₅, resulting in a reduction of 39%. Additionally, ultraviolet rays exhibited a significant ovicidal effect, with hatchability reduced to 26% compared to 73% in the control group. Microwave exposure at a low energy level for 4-6 minutes demonstrated a significant acute lethal effect, reduced progeny, and ovicidal action. Combining microwaves with actellic at LC₂₅ slightly enhanced the lethal effect. In conclusion, this study unveils promising strategies for the effective management of Callosobruchus maculatus, highlighting the potential of ultraviolet rays and microwave energy, either alone or in combination with actellic, while emphasizing the importance of minimizing adverse impacts on both human health and the environment.

Biosorption of Cd²⁺ Ni²⁺ and Zn²⁺ from Contaminated Well Water by Garlic Peel

Fatemeh Soleymani-Bonoti — 2024-06-07

The application of garlic peel was investigated as a low-cost biosorbent for Cd²⁺, Ni²⁺, Zn²⁺, and Pb²⁺ from aqueous solutions in a continuous system. Experiments were carried out in a fixed bed column, and the influence of different flow rates (from 2.0 to 3.3 ml min^-1) on the breakthrough was studied. Column data obtained at different conditions were described using the Bohart-Adams, Thomas, and Yan models. The maximum amount of absorption was obtained for a lead ion with the amount of 490.68 mg g^-1. The column removed 472.78 and 135.17 mg g^-1 of cadmium and nickel ions, respectively, and the minimum value was obtained for zinc ions (55.08 mg g^-1). The garlic peel was regenerated and reused two to four times in successive biosorption-desorption cycles. Differential pulse voltammetry (DPV) was used to measure kinetic models for the biosorption of lead and cadmium ions on garlic peels. Using DPV for lead and cadmium ions, the amount of adsorbed material was obtained at 2.58 and 2.23 mg g^-1 using the pseudo 1st order equation and this value was obtained at 8.26 and 4.70 mg g^-1 using the pseudo 2nd order equation for lead and cadmium ions, respectively. The results show that garlic peel absorbs lead and cadmium ions more than zinc and nickel ions. Because it is made up of several sulfur compounds, sulfur as a soft atom has a stronger interaction with lead and cadmium than other ions.

Systematic Investigation of Selected Bio-molecules Potentially Effective in Inhibiting SARS-CoV-2/COVID-19 via In-Silico Analysis

Akash Vanzara — 2024-05-27

There have been millions of cases of Coronavirus, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high infectious properties during the year 2019. To counter the situation, certain medications were prescribed by health experts, such as Remdesivir, Dexamethasone, Azithromycin and Hydroxychloroquine, following the World Health Organization (WHO) guidelines. While vaccines have since been administered to alleviate symptoms, alternative treatments like Ayurvedic remedies are being explored. This study specifically delves into in-silico analysis using Autodock 4.2.6 software to assess selected phytomarkers against the 6LU7 main protease protein. The chemical structures of these drugs were analyzed using SWISSADME software to evaluate their drug-likeness properties. Molecular docking was conducted using Autodock tools 1.5.6, and receptor-ligand interactions were visualized using PyMol 2.3. Discovery Studio Visualizer 2020 generated a two-dimensional map illustrating bond interactions and distances between drugs and receptors. The mean binding energies of the compounds, including Nobiletin, Tangeretin, Sideroxylonal C, Coriandron, Epicatechin, Epigallocatechin gallate, Luteolin, Ombuin, Tamarixetin, 6-deacetylnimbin, Nimbolide, and Tricin were -5.66, -6.00, -6.46, -6.40, -6.91, -6.51, -6.34, -6.46, -6.99, -6.82, -6.51, -7.85, and -6.35 kcal/mol. Notably, several bioactive markers, including Nobiletin, Tangeretin, Epicatechin, Epigallocatechin gallate (EGCG), Ombuin, Tamarixetin, and Nimbolide, exhibited similar binding sites to synthetic drugs like Remdesivir, such as PHE140, CYS145, GLU166, and GLN189. The investigation also addresses Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) modelling, binding energy scores, and binding affinity, emphasizing the importance of vaccination as a crucial measure to curb the spread of infection.

A New Model to Correlate Solubility of Therapeutic Drugs in Supercritical Carbon Dioxide

Raghavan Amrithaa — 2024-05-13

In this work, a new solubility model was proposed based on the enhancement factor concept. The proposed model is validated with the literature available solubility data of seventeen therapeutic drugs in supercritical carbon dioxide. The correlating ability of the proposed model was compared with the Chrastil model and Bartle et al. model. The global average absolute relative deviation (AARD) percentages of Chrastil, Bartle et al. and new models were 19.42%, 19.57% and 16.43%, respectively. Sublimation enthalpies of therapeutic drugs were calculated with a new model as well as with Bartle et al. model. The calculated sublimation enthalpies ranged between 8.32 to 180.23 kJ/mol and 19.5 to 280.26 kJ/mol for the Bartle et al. model and the Improved Bartle model, respectively. Finally, a statistical analysis was performed in terms of Alaike's Information Criterion (AIC) to differentiate models considered in this work.

Pyrolytic Conversion of Waste High-Density Polyethylene to Wax: Temperature Optimization and Characterization of Wax

Achyut Kumar Panda — 2024-04-25

The formation of wax from waste high-density polyethylene by thermal decomposition through pyrolysis is examined in this work. To get wax from waste high-density polyethylene, the thermal cracking reaction is run in a semi-batch pyrolysis reactor at 550 °C, 600 °C, and 650 °C. The yield percentage, melting point, specific gravity, and penetration degree of wax varied depending on the temperature. At 600 °C, waste high-density polyethylene yielded the highest wax output (87.25%) with a 0.7768 specific gravity, a 59 °C melting point, and an 81.8 mm penetration degree. The fourier transform infrared spectroscopy (FTIR) analysis concluded the presence of aliphatic hydrocarbon compounds (alkane, alkene, alcohol, and cycloalkane), which is also confirmed by gas chromatography-mass spectrometry (GC-MS) analysis. The innovation in this study lies in the systematic exploration and optimization of temperature conditions for wax production from waste high-density polyethylene (HDPE) bottles.

Preparation of Value-added Chemicals via Chemical Looping Pyrolysis of Corn Straws with Ca-Fe Composite Oxygen Carrier

Wenyao Li — 2024-06-21

Biomass chemical looping pyrolysis (BCLPy), which utilizes either reduced or oxidized oxygen carriers for biomass pyrolysis, enables the simultaneous production of high-quality bio-oils and clean syngas. In this study, CLPy of corn straws with a Ca-Fe composite oxygen carrier was investigated to produce value-added chemicals by optimizing both temperature and the mass ratio of oxygen carrier to biomass (OC/B). It has been demonstrated that the reduced Ca-Fe oxygen carrier (Re-OC) promotes hydrocarbon formation and facilitates removal of oxygenated compounds from bio-oils. Under optimal conditions (Re-OC/B = 4:3, T = 650 °C), the relative percentage of benzene, toluene and xylene (BTX) in the bio-oil reaches 27.0 area%, while that of 2-pentenone accounts for 38.0 area% at 550 °C with a Re-OC/B mass ratio of 1:3. The maximum yield based on corn straws approaches 4.7 wt.%. Regarding the oxidized Ca-Fe oxygen carrier (Ox-OC), the relative percentage of 2,3-dihydrobenzofuran (2,3-DHB) reaches a maximum value of 11.6 area% at 600 °C with an Ox-OC/B mass ratio of 2:3. Under catalytic ketonization of Ca₂Fe₂O₅ oxygen carrier, a maximum value of 28.0 area% is achieved with an Ox-OC/B mass ratio of 4:3 at 450 °C. In summary, BCLPy provides a completely new strategy for producing biomass-derived chemicals with added value.

Disinfection of Water by Chlorine, Peracetic Acid, Ultraviolet and Solar Radiations: A Review

Juliana Paggiaro — 2024-04-16

Disinfection is an essential step during water treatment to ensure the microbiological safety of water for human consumption, and over time, it has been improved and better understood. In this context, this review provides a compilation of information, new insights, and perspectives on the main microorganisms present in supply water, their basic structures, and mechanisms of disinfection via chlorine, peracetic acid (PAA), ultraviolet (UV) radiation and solar disinfection (SODIS). Chlorine is the most common chemical disinfectant, however, there is the formation of toxic by-products, which has stimulated the use of non-chlorinated disinfection methods, such as PAA, UV and SODIS. The main advantages of PAA reported in the literature are its high disinfecting power, the non-formation of toxic/carcinogenic by-products, its ability to generate radicals, such as CH₃C(O)O^●, HO^● and HOO^● with or without the use of electromagnetic radiation or thermal energy. The generation of radicals is one of the most used mechanisms to explain the oxidation process during disinfection, which, also prompted studies to use radiation for catalyzing the formation of these radicals. Consequently, physical disinfection processes, such as UV irradiation and SODIS have received significant attention because, in addition to having the ability to damage the RNA (Ribonucleic Acid) and DNA (Deoxyribonucleic Acid) of microorganisms causing their inactivation, these processes also promote the formation of radicals through reactive species that are ubiquitous in natural water. Therefore, the review will be important for studies focused on the process of water disinfection by advanced oxidized processes, especially those that use PAA combined with UV or SODIS.

Sustainable Natural Dyes for Textile Use from Food Industry By-Products: A Review

Noureddine Baaka — 2024-04-23

The valorization of food industry by-products has become very trendy in recent years, several researchers valorized these wastes as sustainable natural colorants for various applications. In this review, the valorization of these by-products in literature as natural dyes in textile application is investigated. Indeed, the history of natural dyes is presented, followed by a study of the advantages and disadvantages of these dyes. Finally, the most significant food industry by-products used as sources of natural dyes for textile applications are listed, along with detailed explanations of their dyeing applications on textile fibers. A special interest is given to natural dyes extracted from food industries wastes of winemaking, olive oil, tomato processing, red pepper by-products and dates paste processing. The majority of studies have demonstrated the strength and superior dyeability of textiles dyed with these waste materials. There have also been assertions that certain fragments have light- and antibacterial-blocking properties.