Kinetics, Isotherms and Thermodynamic Studies on Removal of Divalent Copper using Mallet Flower Leaf Powder as Bio-Adsorbent

The effectiveness and efficacy of Mallet Flower Leaf Powder (MFLP) as a bio-sorbent for the removal of heavy metal copper ions from the aqueous solutions have been studied. Experiments were conducted varying the pH, agitation time, temperature, biosorbent size and dosage as parameters. Speed of the mixing is kept at 200 rpm. The analysis of copper was done by using Atomic Absorption Spectrophotometer (AAS). The adsorption of copper was found to be dependent on pH and a maximum removal of 98.78 % was obtained at an optimum pH of 6.0. The optimum biosorbent dosage was 1 g for an agitation time of 40 min. The biosorption data obtained were validated for the best isotherm. The data collected were verified with the available adsorption isotherms. Experimental data obtained was well represented by Langmuir (RL = 0.161, qm = 5.96 mg/g, R2 = 0.9142), Freundlich (n = 0.64, Kf = 0.79L/g, R2 = 0.9995) and Tempkin (R2 = 0.9083, bT = 267.63) isotherms, indicating favorable biosorption. The experimental data obtained were tested for the best fit and the Freundlich Model has yielded the best correlation with the highest regression coefficient, R2 = 0.9844. Kinetic data has also been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999. For the removal of copper from the solution, bioadsorbent showed a maximum adsorption capacity of 5.96 mg/g. HIGHLIGHTS Removal of divalent copper from the aqueous solution using Mallet Flower Leaf powder Atomic Absorption Spectroscopy, Scanning Electron Microscopy and Fourier transform infrared analysis were used to characterize the Mallet Flower Leaf Powder Kinetic data has been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999 The maximum adsorption capacity of MFLP for copper was found to be 5.96 mg/gm GRAPHICAL ABSTRACT

Study on different parts of moringa oleifera for treating wastewater

In this study Moringa Oleífera (MO) leaves and pods are utilized for the treatment of Methylene Blue (MB) dye solution. The uptake of pollutants by MO leaves and pods are assessed by varying dosages from 0.01g to 0.1g with different agitation time of 5min to 30 min. From the observed results, the maximum removal (96%) occurs by adding MO leaves at 0.08g dosage at the time period of 15minutes. MO pods removes maximum of 45% at the dosage of 0.1g at 30 minutes. It is found that MO leaves are better in removing organic dye than MO pods. The Scanning Electron Microscope (SEM) and Energy Dispersive X Ray (EDX) analysis are carried out to identify the morphological character and elemental composition of the MO leaves and pods. The result shows that the leaves contain more carbon content (33%) than pods (20.3%). Similarly the amount of oxygen is least in leaves thus enhancing the removal of dye particles. The SEM result indicates that the pore development is more in leaves than pods. Finally, Isotherm model was developed for pods and leaves; it is found that MO pods follow Freundlich equation whereas MO leaves follow Langmuir equation.

Facemasks: A Looming Microplastic Crisis

Single-use disposable facemasks have been used as a preventive measure against the ongoing COVID-19 pandemic. However, many researchers have found evidence that these facemasks are being dumped into lakes, rivers, and open garbage dumps. Facemasks have the potential of releasing microplastic fibers into the environment; a phenomenon that has been poorly investigated. Moreover, microplastic fibers composed of plastics have the potential of affecting the flora and fauna of many ecosystems. In this preliminary study, we investigate how many microplastic fibers had been released to the water by KF-AD, KF94, surgical, and FFP1 standard facemasks, which are the most widely available facemask standards in South Korea. The waterbody in our research was mechanically agitated for 24, 48, and 72 h. Findings showed that most of the layers of facemasks are composed of polypropylene. The surgical and KF94 standard facemasks released the highest number of microplastic fibers. Furthermore, under our research conditions, a single facemask can release at least 47 microplastic fibers per day (e.g., KF-AD standard mask), which can lead to the release of at least 1381 million microplastic fibers per day in total in South Korea if 70% of the urban population uses a single mask every day. Moreover, the released microplastic fibers significantly increased when the agitation time extended from 24 to 48 h. This finding suggests that the number of released microplastic fibers is likely to increase drastically.

Applied Rheology as Tool for the Assessment of Chitosan Hydrogels for Regenerative Medicine

The regeneration of soft tissues that connect, support or surround other tissues is of great interest. In this sense, hydrogels have great potential as scaffolds for their regeneration. Among the different raw materials, chitosan stands out for being highly biocompatible, which, together with its biodegradability and structure, makes it a great alternative for the manufacture of hydrogels. Therefore, the aim of this work was to develop and characterize chitosan hydrogels. To this end, the most important parameters of their processing, i.e., agitation time, pH, gelation temperature and concentration of the biopolymer used were rheologically evaluated. The results show that the agitation time does not have a significant influence on hydrogels, whereas a change in pH (from 3.2 to 7) is a key factor for their formation. Furthermore, a low gelation temperature (4 °C) favors the formation of the hydrogel, showing better mechanical properties. Finally, there is a percentage of biopolymer saturation, from which the properties of the hydrogels are not further improved (1.5 wt.%). This work addresses the development of hydrogels with high thermal resistance, which allows their use as scaffolds without damaging their mechanical properties.

Coffee Biomass Encapsulated in Calcium Alginate as Material for Lead (II) Adsorption from Aqueous Solutions

This work aims to study the removal of lead (II) from aqueous solutions with Ca-Alginate (CA) and Coffee-Calcium-Alginate (CCA). The coffee biomass were successfully prepared as the material to be encapsulated in calcium alginate. The characterization of the synthesized CA and CCA was performed using fourier transform infrared and scanning electron microscopy. The method used was batch study. Various factors which affected adsorption efficiency of lead (II) ions by CA and CCA, such as pH, agitation time, and adsorbent dose were investigated for determination of optimum experimental conditions. The result showed that CA and CCA had significant effects on adsorption of lead (ІІ) ions at pH = 4, agitation time of more than 120 min, and the adsorbent dose was 0.05 gram. Moreover, the Langmuir isotherm model showed that maximum adsorption capacity (qm) was 163.66 mg/g and 176.99 mg/g respectively for CA and CCA. The Langmuir isotherm was better described the adsorption equilibrium. Both of the adsorbent fitted to pseudo second order equations. These results demonstrated that CA and CCA show great potential to remove Pb(ІІ) ions from aqueous solutions.

Statistical Modelling and Optimisation of the Biosorption of Cd(II) and Pb(II) onto Dead Biomass of Pseudomonas Aeruginosa

Dead biomass of micro-organisms can be used as biosorbents for the mitigation of heavy metal pollution in the aqueous environment. The aim of this study was to statistically model and optimise the sorption of Cd(II) and Pb(II) by dead biomass of Pseudomonas aeruginosa and to study the interactions between operating conditions. Statistically significant models were obtained for Cd(II) and Pb(II) sorption. The standard deviation for the Cd(II) and Pb(II) models were 0.86 and 1.54 while the coefficient of determination (R2) were 0.9978 and 0.9928 respectively. For both models, the adjusted R2 was in good agreement with the predicted R2 as the difference was less than 0.2. Numerical optimisation revealed that optimum Cd(II) removal of 88.6 % can be achieved at 1.172 ppm initial metal concentration, pH of 8.85, temperature of 43.72 °C, agitation time of 125.96 minutes and dead cell mass of 114.8 mg. Also, an optimum Pb(II) removal of 100 % can be achieved at 1.936 ppm initial metal concentration, pH of 6.88, temperature of 37.24 °C, agitation time of 130.57 minutes and dead cell mass of 122.85 mg. The study has revealed that at careful selected operational parameters, dead biomass of Pseudomonas aeruginosa can be valorised for the removal of heavy metals in aqueous media.

Solvent Extraction of Copper (II) Ions Using Unmodified and Aromatic Amine Modified Red Onion Skin Extract

This study investigated the use of unmodified red onion skin extract (UROSE), aniline modified red onion skin extract (AmROSE) and 2-aminophenol modified red onion skin extract (APmROSE) for the extraction of copper (II) ions from aqueous media. The effect of pH, agitation time, ligand concentration and metal ion concentration on the percentage extraction were explored. The stoichiometric coefficients of the metal ions and the ligands (UROSE, AmROSE and APmROSE) in each extraction experiment were determined using slope analysis. The results revealed that the percentage extraction of copper (II) ions increased with increasing ligand concentration and agitation time and decreased with increasing initial concentration of copper (II) ions. The optimum pH for the extraction of copper (II) was found to be 6.77, 6.10 and 2.57 for UROSE, AmROSE and APmROSE respectively, while slope analysis showed that UROSE, AmROSE, and APmROSE ligands reacted with the metal ion in 1:1 molar ratio.

Influence of Magnetite Dispersion on Tensile Properties

Nanofibers have high cell affinity due to their fine structure and surface roughness, and are expected to be used as biomaterials. In particular, magnetic nanofibers containing magnetic particles are expected to be used for magnetically induced drug delivery systems and hyperthermia. However, due to the aggregation of the magnetic particles contained in the nanofibers, there is a problem that the aggregation location becomes a starting point of fracture and causes a decrease in tensile strength. In this study, to improve the dispersibility of magnetic particles in Magnetite/PLA nanofiber nonwoven fabrics for suppressing the decrease in tensile strength, magnetite is subjected to surface treatment with oleic acid or stearic acid and ultrasonic agitation. Magnetite/PLA nanofiber nonwoven fabric was prepared by the electrospinning method, and dispersion of magnetite in PLA nanofiber nonwoven fabric and tensile strength were evaluated. Magnetite dispersion was improved by the surface treatment and increasing the ultrasonic agitation time. In particular, by performing the stearic acid treatment and prolonging the ultrasonic agitation time, the magnetite dispersion tended to be improved. This treated Magnetite/PLA nanofiber nonwoven fabric showed higher tensile strength.

Response Surface Optimization for an Eradication of Dye onto Ground Nut Shell

The present investigation focuses on an effective dye expulsion in distinction to deliquescent solution using an agricultural dissipation adsorbent. Experiments were conducted on a survey of groundnut shell for sorption of Congo red dye. Several criterions comparatively adsorbate concentration, adsorbent loading, pH, and agitation time effects deliberated by conducting batch studies. Central composite design in Response surface methodology was correlated for optimized process parameters. Interaction effects of both adsorbate and adsorbent were studied with the help of Analysis of Variance.