v. shojaei

A coal waste sample loaded with Fe3O4 nanoparticles is employed as an efficient adsorbent to remove Cd from synthetic wastewater. The synthesized nanocomposite is characterized using the Fourier transform-infrared (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The visual analysis of the microscopic image shows that the mean size of the magnetite nanoparticles is about 10 nm. The effects of the operating variables of the initial solution pH (3-11) and nanocomposite to pollutant ratio (7-233) are evaluated using the response surface methodology on cadmium adsorption. The process is also optimized using the quadratic prediction model based on the central composite design. The statistical analysis reveals that both factors play a significant role in Cd adsorption. The maximum Cd removal of 99.24% is obtained under optimal operating conditions at pH 11 and nanocomposite/cadmium ratio of 90 after 2 h of equilibrium contact time. A study of the adsorption kinetics indicates that the maximum removal could be attained in a short time of about 2 min following a first-order model. The isotherm investigations present that the Cd adsorption on the Fe3O4/coal waste nanocomposite has a linearly descending heat mechanism based on the Temkin isotherm model with the minor applicability parameters than the other isotherm models. The overall removal behaviour is attributed to a two-step mechanism including a rapid adsorption of cadmium ion onto the active sites at the surface of nanocomposite followed by a slow cadmium hydroxide precipitation within the pores over the nanocomposite surface.

The purpose of this study was to identify and validate the indicators and components affecting the International Development of Table Tennis in Iran. From the paradigm perspective, the present study was a type of pragmatism, mixed approach, exploratory-field nature, phenomenological and survey strategy, and applied in terms of purpose. The data collection method was indepth and semi-structured interviews (qualitative section) and a questionnaire. The statistical population of the study was experts from the national tennis teams of Iran, including the coaches of the national tennis teams of Iran, senior managers in the Ministry of Sports and Youth and the Tennis Federation. The coaches of the various tennis leagues, the tennis boards, the staff and experts of the Ministry of Sports and Youth and the Iranian Tennis Federation formed the sample members of the research in a small section. At first 226 initial codes including 13 main categories and 37 pivotal categories regarding the factors affecting the international development of tennis in Iran were counted, totally the number of these codes were 460. The reliability coefficient of qualitative research re-coding was calculated to be 0.84. The apparent and content validity in the form of CVR and CVR forms was approved by experts and the validity of the research questionnaire after performing the exploratory analysis process. Fit of the model with SRMR calculation equal to 0.066 which showed the optimal fit of the model. Economic factors (0.503), social factors (0.438), infrastructure development (0.43) and technical and specialized factors (0.44), motivational factors (0.373), media factors (0.518), the nature of tennis (0.004) ), Talent identification (0.497), managerial factors (0.530), government and governance (0.458), educational institutions and development of public sports (0.472) as indicators and components affecting the international development of tennis are discovered and validated in which all were reported to have high and medium quality upwards with Q2 calculation

A novel bio-composite produced from coal fly ash accompanied by rhamnolipid biosurfactants was produced and used as an efficient adsorbent for the removal of cadmium from aqueous solution. Effects of initial solution pH (3-11) and absorbent to cadmium ratio (40-200) on cadmium removal, as process response, were studied and optimized using a central composite type response surface methodology. Results showed that both factors significantly affect the removal efficiency. Optimum adsorption conditions, resulting in over 99% cadmium removal, were achieved at pH 10 and absorbent to cadmium ratio of 40. Time-wise studies revealed that a maximum removal can be achieved following a classic first order model with a rate of 548.57 min-1. The cadmium adsorption on activated fly ash was also found to follow the Langmuir isotherm model with monolayer adsorption mechanism. Moreover, the bio-composite yielded a maximum adsorptive capacity of 67.11 mg/g. The selectivity study in bimetal aqueous systems using copper, lead and zinc metals also confirmed the high adsorption capacity of bio-composite. This study demonstrated that rhamnolipid-fly ash bio-composite could be considered as a promising efficient, low-cost resource material for the treatment of heavy metal polluted wastewaters.