حمید خوشدست

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.

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.

One of the biggest concerns about the increasing development of the mining industries, especially in the dry and tropical regions, is their high water consumption and, consequently, the serious threat to the local water resources as well as the impacts of these industrieschr('39') pollution on the environment and other downstream water resources. Therefore, it is necessary to make appropriate decisions and take appropriate measure to manage water consumption in the mining industry. However, the presentation of any operational plan to control water use in such industries depends on the planned and scientific monitoring of water consumption over specific periods.

In this study, water consumption monitoring in the Gohar-Zamin Iron Ore Complex (Sirjan, Iran) was investigated for the first time using Shewhart statistical monitoring method. For this purpose, water consumption data of the plantchr('39')s dual processing lines were collected and organized during one year of operation to develop the control charts.

The results show that in different months of the year, water consumption can be independent of the weather conditions or the factory production. Moreover, the cumulative diagrams show that the trend of water consumption in the two lines is almost opposite to each other and each month with increasing water consumption of one line, water consumption of the other line has decreased.

To alleviate these problems, expediting the construction of tank No.2 was proposed as the best operational solution for independent water consumption of each processing line.

Engineering education is a two-phase system of tuition and manner, which any lack of attention to each leads to upbringing professionals inefficient in both material and mental points of view, respectively. The manner phase makes engineer capable of communicating, arguing, reasoning, and making decision in the most impressive manner. Hence, the education of engineering ethics at university might prepare students to face the professional life readily. This ability is possible if only they are educated in the light of an organized new curriculum program. The aim of the current paper is to support such a modified program. The proposed curriculum map includes four parts of scopes, topics, teaching methods, and outcomes, regulated at four levels. These parts would be upgraded from fundamentals of engineering profession up to moral evaluations and criticisms.