Removal of lead and cadmium ions by single and binary systems using phytogenic magnetic nanoparticles functionalized by 3-marcaptopropanic acid

The present research study is focused on green fabrication of superparamagnetic Phytogenic Magnetic Nanoparticles(PMNPs), and then its surface functionalization with 3-Mercaptopropionic acid(3-MPA). The resulting material(i.e. 3-MPA@PMNPs) characterized by FTIR, powder XRD, SEM, TEM, EDX, VSM, BET and TGA techniques and then further employed for the investigation of the adsorptive removal of lead(Pb^2+) and cadmium(Cd^2+) ions from aqueous solutions in single and binary systems. The material showed fastest adsorptive rate(98.23%) for Pb^2+ and(96.5%) Cd2+within the contact time of 60 min at pH 6.5 in the single system. The experimental data were fitted well to Langmuir isotherm, indicated monolayer adsorption of both metal ions onto 3-MPA@PMNPs and an estimated comparable adsorptive capacity of 68.41 mg·g^-1(Pb2+) and 79.8 mg·g^-1(Cd2+) at p H 6.5. However, kinetic data agreed well with pseudo-second-order model, and indicated that the removal mainly supported chemisorption and/or ion-exchange mechanism. Thermodynamic parameters such asΔGo,ΔHo, and ΔSo, were-3259.20, 119.35 and 20.73 for Pb^2+, and-1491.10, 45.441 and 7.87 for Cd^2+ at temperature 298.15 K, confirmed that adsorption was endothermic, spontaneous and favorable. The material demonstrated higher selectivity of Pb2+ and its removal efficiency was(98.20 ± 0.3)% in binary system experiments. The material persisted performance up-to seven(07) consecutive treatment cycles without losing their stability and offered comparable fastest magnetic separation(35 s) from aqueous solutions. Therefore, it is recommended that the prepared material can be employed to remove toxic heavy metal ions from water/wastewaters and this "green" method can easily be implemented at large scale in low economy countries.

Assessment of plastic degradation by indigenous bacteria from waste disposal sites

The present study focuses on the isolation of bacterial pathogens from waste disposal sites,and examination of their efficiencies for degrading various plastics.Seven bacterial isolates such as E.coli,Corynebacterium spp.,Micrococcus spp.,Azotobacter spp.,Pseudomonas spp.,Staphylococcus spp.,and Bacillus spp.were identified.Bacillus spp.exhibited the highest percentage reduction in black plastic weight(47.46%),while Corynebacterium spp.,and E.coli achieved a maximum reduction of 45.76 and 46.42%for pink plastic respectively.Pseudomonas spp.and Micrococcus spp.demonstrated notable reductions of 46.43%and 56.60%in white and Canteen Stores Department(CSD)biodegradable plastics,respectively.Optical density(OD)measurements revealed that bacterial isolates achieved maximum OD values with CSD plastics,emphasizing their proficiency in plastic degradation.Fourier Transform Infrared Spectroscopy(FTIR)confirmed the degradation process,with a decrease in the peak value from 2916 to 2914 cm^(-1) for pink plastic,signifying alkane,and alkene presence.Three new peaks at 1398,1371,and 1361 cm^(-1) in the FTIR spectrum of CSD plastic indicated presence of alcohol.Scanning Electron Microscopic(SEM)micrographs illustrated bacterial colonization,cracks,and spots on plastic surfaces,while Xray Diffraction(XRD)spectra showed peaks at 4.083,3.705,3.020,and 1.909,suggesting plastic degradation.In conclusion,soil of waste disposal site harbored diverse microbial species,and have highlighted their effectiveness in mitigating environmental pollution by degrading hazardous plastic waste.