Universal Journal of Green Chemistry

A Factorial Design Assessment of Marine Exoskeleton-Based Bio-sorption of Relevant Electroplating Metals

2022-09-07T11:54:24+08:00

A preliminary assessment of the capacity of pulverized crab shells to function as bio-sorbents for the removal of selected metals, zinc, cadmium, and chromium was analyzed according to a factorial experimental design. These metals were chosen because they have little precedent in past sorption studies and represent metals discharged into receiving waters by the electroplating industry. The design was done to assess parameters that have the highest impact on adsorption capacity and removal efficiency. Validation with other heavy metal ion removals was performed for comparison followed by a factorial 33 DOE using JMP®. It was found that for zinc, adsorbent amount, pH, time and the interaction of adsorbent amount*time and pH*adsorbent amount have the highest significance. For cadmium, only adsorbent amount is significant. Finally, chromium uptake was strongly dependent on adsorbent amount and pH. According to ionic radius theory, the favorability for adsorption is according to the following trend: chromium > cadmium > zinc; however, under our set of experimental conditions, the order was: cadmium > zinc > chromium because the presence of calcium carbonate exerts a major role in their sequestration.

Removal of Heavy Metal Ions (Fe2+, Mn2+, Cu2+ and Zn2+) on to Activated Carbon Prepared from Kashmiri Walnut Shell (Juglans regia)

2024-05-06T14:50:32+08:00

Heavy metal pollution poses significant threats to the environment and human health, even at trace concentrations. In this study, activated carbon derived from Kashmiri walnut shell (Juglans regia) was investigated for its potential to adsorb heavy metal ions (Fe2+, Mn2+, Cu2+, and Zn2+). Standard solutions containing heavy metal ions at concentrations ranging from 10 to 50 ppm were prepared for adsorption experiments, i.e., at temperature 25 ◦C, and adsorbent dosage 1 g using a column mechanism. The activated carbon was first treated with 0.1M HCl and 0.5M ammonia solutions, and then washed with demineralised water. Subsequently, the metal ion solutions were passed through the column individually, and the filtrates were analyzed for heavy metal ion presence. The experimental results demonstrated that walnut shell-derived activated carbon exhibited promising adsorption capacity spanning from 0.36 mg/g for Zn2+, 0.5 mg/g for both Mn2+ and Cu2+ and 0.54 mg/g for Fe2+ thus showing the adsorption trend as Fe2+ > Mn2+ = Cu2+ > Zn2+. This study highlights the potential of using walnut shell-derived activated carbon as an effective and cost-efficient method for mitigating heavy metal pollution in contaminated water sources.

Green Oxidation of Menthol in Multigram Scale Based on Calcium Hypochlorite

2024-05-08T08:50:57+08:00

The oxidation reaction stands as a fundamental process in organic synthesis, holding significant importance in generating various value-added chemical products. Oxidative processes are pivotal realms for both industrial and academic exploration. Present-day scientific and research pursuits emphasize the imperative need for chemistry to evolve towards absolute sustainability, prioritizing safety, intelligence, and environmental friendliness—thus aligning with the principles of green chemistry. This work aims to report a green oxidation procedure of menthol to menthone in multigram scale, using calcium hypochlorite as reagent, that can be use in academy research or practical class.

RGO/ZnCo2O4 Composites as an Electrode Material for High-Performance Supercapacitor Application

2024-05-24T10:58:52+08:00

Recently, composite material-based supercapacitors have attracted a lot of attention due to their enhanced
performance. In this work, we present a facile synthesis of RGO/ZnCo2O4 direct solution-based composites through a hydrothermal route anchored on nickel foam. ZnCo2O4 nanospheres wrapped under ribbon-like RGO nanosheets combine the synergistic properties of both in the form of hybrid electrode material. As a result, the RGO/ZnCo2O4 electrode exhibits a specific capacitance of 755.38 F/g at a scan rate of 5 mV/s with improved cyclic stability up to 2000 cycles. In addition to this, the hybrid electrode material also shows a good value for energy density and power density as 10.75 Wh/kg and 1500 W/kg at a current density of 1 A/g with 93.47% efficiency. This study thus signifies that the synergistic effect of both the electrodes in combination as a hybrid gives a better performance than the individual ones.

Usefulness of the Biomass of Tobacco (Nicotiana tabacum) for The Elimination of Chromium (VI) from Polluted Waters

2022-12-29T17:46:47+08:00

The tobacco plant is capable of accumulating heavy metals in its different parts, making it a good candidate for use in bioremediation, although there are few reports in which the biomass of this plant is used for the removal of heavy metals in solution. Also, cigarette residues are an environmental problem, so the use of these residues is an opportunity to obtain biomass for the removal of heavy metals from polluted environments. The objective of this work was to determine the removal capacity of Cr (VI) by commercial tobacco biomass, finding that 1 g of biomass removal 72 mg/L of the metal at 24 h, pH 2.0, 28 °C and 100 rpm, while at higher temperatures the removal is higher, and if the concentration of the metal is increased (1 g/L), its removal capacity is reduced, since 64.72% is removed at 24 h at 28 °C, although at 60 °C, 1 g/L is removal at 8 hours. If the concentration of the bioadsorbent is increased, the metal removal does not increase. Finally, 5 g of biomass eliminates 66.1% and 74% of Cr (VI) present in naturally contaminated soil (100 mg/g) and water (100 mg/L), respectively.

A Green Route for Sustainable Nanoporous Solid Acid Catalyst Synthesis Using Bio Template and Analysis of Its Progressive Transformation of CO2

2024-01-31T16:07:54+08:00

Green chemistry approach is a most important area in the modern chemical world. The nano (meso) porous materials have the specific application in separation, adsorption and catalysis. A green template (Egg white) is used as a bio template for the synthesis of nanoporous material to replace the hazardous templates. It is a bio-degradable template; it does not create any environmental issues. The synthesized material is characterized by various spectroscopic techniques to confirm its structural formation. Based on pore size, the catalyst named as AlSiO₄-14. The synthesized catalyst (AlSiO₄-14) is active at 175^oC. This low temperature activity will not produce coke formation at the same time it does not require any regeneration and the catalyst is continuously active for catalytic reactions. The catalytic activity of carbon dioxide decomposition is achieved at lower temperature. The complete carbon dioxide decomposition of AlSiO₄-14 is 43 % is a great impact of the material.

Biodegradable Cutting Fluids Evaluation for Sustainable Machining Processes

2024-04-26T14:47:03+08:00

Sustainably selecting the best cutting fluid among alternatives, considering various weighted criteria or factors, is a complex problem encountered by machine operators in engineering workshops worldwide. The aim of this work is to utilize the Multi-Attribute Utility Theory (MAUT) decision-making model for biodegradable cutting fluids selection in a machine shop. The objectives of the work include carrying out a step-by-step process of the MAUT method on biodegradable cutting fluid alternatives. Therefore, this study utilizes the MAUT decision-making method for selecting the best biodegradable cutting fluid among a set of five (5) alternatives namely soybean oil, palm oil, polyalphaolefin, trimethylpropane trioleate and polyethylene glycol. The cutting fluids were evaluated based on criteria such as heat dissipation, stability, lubrication and cost-effectiveness. From the results, Polyalphaolefin is the best alternative, ranking first according to the global utility scoring. Therefore, Polyalphaolefin had a global utility score of 0.688, followed by Polyethylene Glycol which had a score of 0.600, followed by Trimethylpropane Trioleate which had a score of 0.588, followed by Soybean Oil which had a score of 0.363 and finally, Palm Oil which had a score of 0.263. This study provides a procedure for implementing the MAUT method of decision-making for cutting fluids selection within engineering workshops for sustainable machining practices.

Design and Analysis of the Waste Heat Recovery System for Stenter Exhaust

2023-10-27T17:21:58+08:00

In this study, combined with the exhaust adsorption, desorption and catalytic combustion technology, a waste heat recovery scheme using stenter exhaust to heat desorbed air and preheat stenter suction air was proposed. Using Aspen Plus to design the waste heat recovery system, and using Aspen EDR to design the structure of heat exchangers. The energy utilization efficiency of waste heat recovery system was evaluated through the exergy analysis, and the influence of exhaust flow rate variation on exergy efficiency of heat exchanger under different exhaust temperatures were discussed. Moreover, the influence of fluid parameter variations on the heat transfer process was also analyzed. Finally, the economic calculation was carried out and the overall energy-saving effect of waste heat recovery system was demonstrated. The results showed that the utilization of this waste heat recovery system can recover 537 kW, the exergy efficiency of desorbed air heat exchanger and preheating air heat exchanger were 51% and 58.9% respectively. In terms of the economic evaluation, the annual energy-saving economic benefits was about $ 89,312, and the static investment payback period was 1.17 years.

Simulating Studies on Phosphate (PO43−) Removal from Laundry Wastewater Using Biochar: Dudinin Approach

2024-04-02T10:26:41+08:00

Wastewater from the Laundry wash processes contain a diverse range of chemical pollutants that can have detrimental effects on human health and the environment. In this study, simulation studies by Spyder Python software v3.2 to assess the efficacy of biochar in removing PO43− from wastewater were conducted. Through modelling and simulation, the mechanisms involved in the adsorption process of phosphate by biochar were studied by altering variables that are specific to the phosphate from common laundry detergents. These included aqueous solubility, initial concentration, and temperature using Dudinin and Astakhov (DA). Results showed that concentration equilibrates near the highest concentrations for CaO-rich biochar-120 mg L−1, Pine sawdust biochar-57 mg L−1 while Peanut, Eucalyptus polybractea and Crawfish biochar equilibrated at near concentration. CO2-activated Thalia, Sewage sludge, Broussonetia papyrifera Leaves biochar equilibrated just at the lower concentration. Soyer bean Stover biochar exhibited a sharp rise and fall peak in mid-concentration at 130 mg L−1 Volume. The modelling results were consistent with experimental findings from literature ensuring the accuracy, repeatability, and reliability of the simulation study. The simulation study provided insights into adsorption for PO43− from wastewater by biochar using concentration per volume that can be ideally adsorbed under the given conditions. Studies showed that applying the principle experimentally in real wastewater with all its complexity is warranted and not far-fetched.

Degradation of Organic Compounds in Aqueous Media using Semiconductor Nanomaterials

2024-04-29T10:10:09+08:00

A Recent Trends on Green Synthesis and Bioactivity of Imidazole

2024-03-01T12:00:58+08:00

Imidazole is a five-membered, planar heterocyclic ring made up of 3C, 2N, and N in the 1st and 3rd places. Purine, histamine, histidine, and nucleic acid are only a few significant natural compounds that contain the imidazole ring. It is utilised as a cure to optimize the solubility and bioavailability properties of proposed weakly soluble lead compounds since it is an aromatic chemical that is polar and ionizable and so improves the pharmacokinetic features of lead molecules. Derivatives of imidazole have a special place in medicinal chemistry. An essential synthesis technique in the process of discovering new drugs is the integration of the imidazole nucleus. Due to the remarkable therapeutic efficacy of medications related to imidazole, medicinal chemists have been inspired to create numerous innovative chemotherapy agents. This review summarized the work that has been done in recent years about different synthetic approaches of imidazole derivatives and their potential activity as anti-HIV, anticancer, anticovid, antifungal, antidiabetic, antidepressant, antioxidant, and antituberculosis.