RESUMO
The issue of environmental contamination, particularly caused by the existence of heavy metal particles, is a major and widely recognized subject that receives substantial global attention. The remediation of Cu(II), Cd(II), Ni(II), and Pb(II) ionic metal particles from synthetic wastewater using chemically treated plant leaves of Ageratum conyzoides (TAC) as a biosorbent was investigated. The biosorption process was implemented utilizing a batch system, wherein several operational parameters were considered, including temperature, pH, agitation time, biosorbent dosage, and initial concentration of the metal ion. Langmuir, Freundlich, Temkin, and D-R isotherm models were used to evaluate equilibrium data. The analyzed parameter exhibits characteristics that were best fitted with the Langmuir isotherm. The observed biosorption capacities (qm) of Cu(II), Pb(II), Ni(II), and Cd(II) ions on the TAC were measured as 51.573, 30.49, 33.53, and 35.91 mg/g, respectively, at a temperature of 22 °C. The affinity sequence of these metal ions follows the order Cu(II) > Pb(II) > Ni(II) > Cd(II). The measured values for the biosorption free energy change (ΔG) of Cu(II), Pb(II), Cd(II), and Ni(II) metal ions ranged from -1.017 to -4.723, -1.368 to -3.612, -2.785 to -5.21, and -1.047 to -5.135 kJ/mol, respectively. The enthalpy (ΔH) for Cu(II), Pb(II), Cd(II), and Ni(II) were determined to be +19.33, +6.82, +14.83, and +38.07 kJ/mol, respectively. Similarly, the corresponding entropy changes (ΔS) for the same series of metal ions were recorded as +0.075, +0.064, +0.063, and +0.135 kJ/mol.K. The pseudo-second-order kinetic models yielded superior outcomes in comparison to the pseudo-first-order kinetic models. The findings of the experiment indicated that the TAC demonstrates favorable efficacy in extracting all four metal ions. Hence, the utilization of biomass derived from Ageratum conyzoides leaves has proven to be a viable and economically feasible approach for biosorption of all four metals.
RESUMO
PURPOSE: To assess the characteristics of completed panretinal photocoagulation (PRP), using ultra-widefield imaging in proliferative diabetic retinopathy. METHODS: Quantitative assessment of ultra-widefield imaging images of 133 patients with proliferative diabetic retinopathy with completed PRP was made using ImageJ software. The parameters assessed included distance of laser spots from the optic disk, foveal center, superior and inferior arcades, and extent of the maximum width of laser. Areas assessed were total area of the image, area of the inner limit within which laser spots are restricted, minimum areas of unlasered patches, total area lasered, and ideal area to be covered by PRP. RESULTS: Two hundred one images were assessed for the final analysis. The mean distance of laser spots was 4.2 ± 2.4 mm from the optic disk (nasal) and 6.6 ± 2.5 mm from the foveal center (temporal). The mean distance of laser spots from the superior arcade vessel was 3.2 ± 1.9 mm and 6.2 ± 4.4 mm from the inferior arcade. The mean area of the retina that should have been ideally lasered was found to be 900 ± 267 mm 2 , and the actual area lasered was found to be 681 ± 254.4 mm 2 . CONCLUSION: Approximately one-quarter area of the retina continues to remain ischemic because of the lack of inadequate coverage of PRP. Further longitudinal studies are recommended, using ultra-widefield imaging to objectively assess the adequacy of PRP and its role in modulating the course of progression of the retinopathy.