ABSTRACT
Radioactive iodine isotopes especially 131I are used for diagnosis and treatment of different types of cancer diseases. Due to the leak of radioactive iodine into the patient's urine in turn, the wastewater would be contaminated, so it is worth preparing a novel adsorption green material to remove the radioactive iodine from wastewater efficiently. The removal of 127I and 131I contaminants from aqueous solution is a problem of interest. Therefore, this work presents a new study for removing the stable iodine 127I- and radioactive iodine 131I from aqueous solutions by using the novel nano adsorbent (Nano ZnO/MWCNTs) which is synthesized by the arc discharge method. It is an economic method for treating contaminated water from undesired dissolved iodine isotopes. The optimal conditions for maximum removal are (5 mg/100 ml) as optimum dose with shacking (200 rpm) for contact time of (60 min), at (25 °C) in an acidic medium of (pH = 5). After the adsorption process, the solution is filtrated and the residual iodide (127I-) is measured at a maximum UV wavelength absorbance of 225 nm. The maximum adsorption capacity is (15.25 mg/g); therefore the prepared nano adsorbent (Nano ZnO/MWCNTs) is suitable for treating polluted water from low iodide concentrations. The adsorption mechanism of 127I- on to the surface of (Nano ZnO/MWCNTs) is multilayer physical adsorption according to Freundlich isotherm model and obeys the Pseudo-first order kinetic model. According to Temkin isotherm model the adsorption is exothermic. The removal efficiency of Nano ZnO/MWCNTs for stable iodine (127I-) from aqueous solutions has reached 97.23%, 89.75%, and 64.78% in case of initial concentrations; 0.1843 ppm, 0.5014 ppm and 1.0331 ppm, respectively. For the prepared radio iodine (131I-) solution of radioactivity (20 µCi), the dose of nano adsorbent was (10 mg/100 ml) and the contact time was (60 min) at (pH = 5) with shacking (200 rpm) at (25 °C). The filtration process was done by using a syringe filter of a pore size (450 nm) after 2 days to equilibrate. The removal efficiency reached (34.16%) after the first cycle of treatment and the percentage of residual radio iodine was (65.86%). The removal efficiency reached (94.76%) after five cycles of treatment and the percentage of residual radio iodine was (5.24%). This last percentage was less than (42.15%) which produces due to the natural decay during 10 days.
ABSTRACT
Background: To report the prevalence of acquired symptomatic external punctal stenosis (EPS) in a tertiary referral center in Kuwait, and to study the associated risk factors, etiologies, and management outcomes. Methods: This prospective interventional hospital-based study was performed at the Farwaniya governmental hospital in Kuwait between November 2018 and November 2019. All patients were referred to the oculoplastic clinic with symptomatic epiphora, age > 18 years, epiphora Munk score ≥ 0, tear film meniscus ≥ 2 mm, and punctum with grade ≤ 2 (smaller than normal size, but recognizable) were included. Eclusion criteria were congenital causes of epiphora, previous eyelid surgeries, and traumatic or neoplastic causes of punctal or canalicular obstruction. Results: A total of 418 patients with symptomatic epiphora, who were referred to our oculoplastic clinic, were enrolled in our study. The prevalence of EPS was 70.3%. Eamination of the puncta revealed different shapes, including tangential, pinpoint, elevated, slit-shaped, horse shoe-shaped, and membranous puncta, with the tangential type accounting for the greatest proportion (65.3%). Bilateral punctal stenosis was observed in 206 patients (70.1%) and unilateral involvement in 88 patients (29.9%). Dilatation and syringing were performed for all puncta upon diagnosis, and repeated dilatation was performed for 225 puncta (32.7%). Placement of a Mini-Monoka tube was performed in 11 puncta (1.6%). Conclusions: EPS was a common cause of symptomatic epiphora in our study. Aging and female sex were identified as common risk factors. Most etiological factors of EPS were associated with a pathophysiological inflammatory mechanism. For exact estimates of its prevalence, a population-based study is necessary in future.
