Utilization of Modified Attapulgite for the Removal of Sr(II), Co(II), and Ni(II) Ions from Multicomponent System, Part I: Kinetic Studies.

Radionuclide sorption by natural and modified clays is extensively accepted to be an important process from the radioactive waste point of view. This work focused on modification of natural attapulgite with a layered double hydroxide to produce a novel chemisorbent for Sr2+, Ni2+, and Co2+ removal from multicomponent solution. The structural and surface characteristics of both attapulgite (ATP) and modified attapulgite (LDH-ATP) were investigated using XRD, FTIR, SEM, and thermal analysis. Comparison of sorption features of Sr2+, Ni2+, and Co2+ onto ATP and LDH-ATP was achieved; the results indicated that LDH-ATP was the most efficient sorbent for Sr2+, Ni2+, and Co2+. Kinetic studies established that the sorption is fast and reaching >90% within 30 min. The sorption of Sr2+, Ni2+, and Co2+ are well defined by non-linear pseudo-second-order model and controlled by an intra-particle diffusion mechanism. The diffusivity was determined using homogeneous surface diffusion (HSDM) model and found in the order 10-13 m2/min; this confirmed that the sorption of the three ions is chemisorption process. LDH-ATP can be employed as a candidate chemisorbent for the removal of some metal ions from waste solution.

Facile radiolabeling optimization process via design of experiments and an intelligent optimization algorithm: Application for omeprazole radioiodination.

The major uses of radiopharmaceuticals (RP) in clinical areas are diagnosis and/or therapy. The present study aimed to utilize the application of fractional factorial design analysis (FFDA) coupled with particle swarm optimization algorithm (PSO) to assess the optimization of RP production process. In this regard, omeprazole (OMP), which is gastric parietal cell proton pump inhibitor (PPI), was radiolabeled with iodine-125 (125 I) isotope in order to be used as a radiotracer for stomach imaging. Different factors that affect radiolabeling process were studied. According to the proposed design, just 16 experimental runs of radiolabeling process were performed using the extremes of each factor. In addition, one run was executed at the mean point of each factor. Undesirable maximum radiolabeling yield (RY) of radioiodinated omeprazole (125 I-OMP) was deduced from application of FFDA (88.4%). Furthermore, after applying PSO with changing limits of one factor, the maximum RY of 125 I-OMP was found to be 93.78%. Moreover, the practically verification from optimum conditions, which obtained from PSO, was found to give an RY of 93.99%. Overall, the findings of this study confirmed the potential use of that hybrid design for optimization of radiolabeling processes.