Synergistic Enhancement of Diagnostic Imaging: Synthesis and Preliminary Safety Evaluation of Gadolinium-Doped Carbon Quantum Dots as Dual-Contrast Agent

The present study explores the synthesis and bio-safety evaluation of gadolinium-doped carbon quantum dots (GCQDs) as a potential dual-contrast agent for diagnostic imaging. GCQDs exhibit both fluorescent and magnetic properties, making them suitable for UV-Vis and magnetic resonance imaging (MRI). The synthesis of GCQDs was achieved via hydrothermal treatment, incorporating gadolinium into the carbon quantum dot matrix. The magnetic properties of GCQDs were analyzed, showing significantly enhanced values compared to gadobutrol, a common MRI contrast agent. However, synthesis constraints limit the gadolinium content achievable in nanodots. To assess the safety of GCQDs, their effects on the embryonic development of zebrafish (Danio rerio) were examined. Various concentrations of GCQDs were tested, observing mortality rates, hatchability, malformations, heartbeats, spontaneous movement, and GCQDs uptake. Dialysis studies indicated that gadolinium ions are incorporated into the internal structure of the carbon nanodots. Zebrafish toxicity tests revealed that while survival rates were comparable to control groups, hatchability decreased significantly with higher gadolinium concentrations in GCQDs. Fluorescence microscopy showed no statistical differences in the fluorescence intensity between groups. These findings suggest that GCQDs could serve as an effective dual-contrast agent, combining the optical imaging capabilities of CQDs with the enhanced MRI contrast provided by gadolinium. This study underscores the need for further research on the synthesis methods and biological interactions of GCQDs to ensure their safety and efficacy in medical applications.

Chemically modified Quercus dilatata plant leaves for Pb (II), Cd (II), and Cr (VI) ions remediation from aqueous solution

The current investigation deals with the removal of Pb (II), Cd (II), and Cr (VI) ions by using chemically modified Quercus dilatata leaves (CMQDL) treated with nitric acid (HNO3), and calcium chloride (CaCl2). Batch biosorption experiments were performed to determine the optimal conditions of pH, biomass dose, temperature, contact time, and initial metal concentration for the utmost removal of heavy metals from water. The structural morphology and functionalities were explained by SEM and FTIR analysis. The maximum biosorption capacities for remediation of Pb (II), Cd (II), and Cr (VI) ions via CMQDL were 17.54, 20.408, 20.83 mg g−1, respectively at the optimal conditions. The Langmuir and Freundlich isotherm were applied to explore the equilibrium data however Freundlich isotherm model best evaluate the equilibrium data with high regression correlation coefficient (R2) values of 0.985, 0.826, and 0.919 for the elimination of Pb (II) Cd (II), and Cr (VI) ions, respectively. The kinetic study proposed that the remediation operation best obeyed the kinetic pseudo 2nd order model. The calculated thermodynamics functions like change in entropy (ΔS°), change in enthalpy (ΔH°) and Gibbs free energy (ΔG°) revealed that the removal of Pb (II) ions via the CMQDL was viable, exothermic and spontaneous, Cd (II) was endothermic and spontaneous and Cr (VI) was endothermic and non-spontaneous. The current study explored that CMQDL can be used for the remediation of Pb (II), Cd (II), and Cr (VI) ions, respectively.

Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

In the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) usingPseudomonas aeruginosastatic biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1and a detection limit of 6.25 μg L-1for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

Coagulation of Metallic Pollutants from Wastewater Using a Variety of Coagulants Based on Metal Binding Interaction Studies

In this study, different organic (moringa and neem leaf powder) and inorganic (alum) coagulants were used for the wastewater treatment. Results revealed that all the coagulants at various doses significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. The maximum decrease in all the attributes was observed when 10 g of coagulants were used. Similarly, maximum adsorption potential was observed in case of moringa leaf powder. Maximum decrease in all physiochemical attributes such as pH (13%), EC (65%), turbidity (75%), total dissolved solids (TDS; 51%), total suspended solids (TSS; 48%), total hardness (TH; 29%), chloride contents (66%) and phosphate contents (44%) was observed. Regarding the heavy metals, maximum decrease for Cadmium (Cd; 96%), Lead (Pb; 88%), Arsenic (As; 23%), Iron (Fe; 90%), Manganese (Mn; 96%) and Zinc (Zn; 48%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was moringa leaf powder > Alum > neem leaf powder. However, the maximum effect of coagulants was observed in case of textile wastewater as compared to the hospital wastewater. Based on the analyses, it is concluded that the moringa leaf powder has maximum adsorption potential for the remediation of wastewater.