Sharif Digital Repository

Leachate migration from solid waste landfills into the subsurface environment is one of the significant problems of landfills. This can cause lots of problems for local soil and water to sources according to the contaminants appear in the leachate. Usually, landfill sites include at least one compact clay liner to prevent contamination of groundwater by produced leachate. Over the last decades investigators have been attracted to the structure and removal capacity of this liner. In this study, the effect of the addition of Zeolite to Kaolinite soil for the removal of heavy metal (manganese and zinc) from landfill leachate and the effect of decreasing the thickness of the soil layer has been... 

The first report of anti-aggregation-based sensor arrays is presented. The strategy is based on the competitive interaction of citrate-capped gold nanoparticles (AuNPs) and heavy metal ions (i.e., Hg(II), Ag(I), Fe(III), and Pb (II)) with three aggregation reagents (i.e., cysteine, melamine, and arginine). In the presence of aggregation reagent,the color and UV–vis spectra of AuNPs are changed indicating the aggregation ofAuNPs. Addition of the aggregation reagents which are firstly treated with the ions, causes AuNPs turn from the aggregation to the dispersion state. The anti-aggregation capability of ions towards various aggregation reagents is different because of distinct stability... 

In this thesis, it reports the fabrication of novel magnetic nanocomposites combining the unique properties of magnetic nanoparticles and cross-linked basic polymers that their surface functionalized by suitable groups such as carboxylate groups, pentaethylenehexamine and so on to achieve the maximum adsorption capacity of dyes and heavy metal ions. The performance of the magnetic nanocomposites for removal of anionic and cationic dyes and heavy metal ions were evaluated in different conditions of pH, contact time and initial concentrations. Moreover, the adsorption mechanism was investigated by kinetic models and isotherm studies. The results showed that the abovementioned adsorbents can... 

The present study was aimed at investigating the use of platinum and platinum nanoparticles stabilized on zeolite as catalyst for the reduction reaction of p-nitrotoluene as one of the dangerous pollutants. The adsorption properties of platinum based on zeolite have been studied for some heavy metals. Monodispersed platinum nanoparticles were synthesized through reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer, and then were immobilized on four types of zeolites. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. In order to investigate the catalytic properties, operating... 

This study focused on the investigation of bioleaching of heavy metals from incinerator ash using Thiobacillus thiooxidans. Eight factors were examined for their significance on bioleaching using a Placket-Burman factorial design. Four significant variables (pulp density, Initial pH, sulfur Concentration and inoculation amount) were selected for the optimization studies. The combined effect of these variables on metal bioleaching was studied using a central composite design. Second order polynomials were established to identify the relationship between the recovery percent of the metals and the four significant variables. The optimal values of the variables for maximum metals bioleaching... 

Industrial wastewater treatment has always been one of the significant human being problems for the years. In particular, sewage containing heavy metals that, if discharged into nature, would have irreversible effects on the ecosystem and human health. Due to their toxic nature, heavy metals will reduce the efficiency of wastewater treatment systems if they are not efficiently treated. Also, the removal of Nitrate from the wastewater, which is one of the most stable nitrogen oxides, has always been a serious human problem in the treatment of effluents due to their high solubility in water. The simultaneous presence of nitrate and heavy metals in the effluent will cause many problems in the... 

Today, with expanding industries, wastewater treatment of them is a global problem. Heavy metal is one of the most common and most dangerous contaminants in waste water that over time, with the strict standards of output, find more effective ways of eliminating them has always been a challenge. New methods, especially in the field of adsorption have achieved promising results in many cases.
Polymers composites are one of the adsorbent for the removal of these contaminants have been considered. In this project Aniline and composites to remove arsenic and chromium were studied. In polymers synthesis factors like type of additives and oxidizing materials strongly effected on morphology of... 

Celery residue modified with H2SO4 was utilized as a low-cost adsorbent for removal of hazardous dyes (methylene blue, malachite green and congo red) and heavy metals (Pb(II) and Cd(II)) from aqueous solution in batch adsorption process. Also, celery residue modified with cationic surfactant (CTAB) to enhance the removal of congo red (anionic dye). The treated and untreated adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The efficacy of dye removal of the modified celery residue was investigated by varying adsorbent dose, contact time, pH, initial dye concentration, and temperature. Experimental data were fitted by three... 

Purification of waste water containing metal ions, is one of major environmental problems which have threaten human’s life, other creatures and even agricultural products by means of polluting suberranean water. Copper ion is one of dangerous heavy metals that exists in potable water and agricultural uses, due to serious problems in health of humans and aquatic. In recent years, different methods for purification of waste water containing heavy metal ions have been published. Right now, thorough these methods such as: filtration, coagulation, precipitation and adsorption are being used, which have their own advantages and disadvantages.In this research, new method for purification of waste... 

Novel zeolite-based micromotors consisted of silver-exchanged zeolite core and three different partial catalytic coatings (Mg/Au, Pt and Ag) were synthesized to eliminate the biological and chemical contamination from water in a fast and efficient way. These engines are benefited by the adsorption capacity and antibacterial activity of silver-zeolites in combination with the autonomous propulsion of catalytic micromotors. The remarkable bactericidal capacity of these particles relies on reactive silver ion released from zeolite and accordingly, increased chance of contact with bacteria during movement. These motors showed rapid killing of bacteria and effective elimination of the Pseudomonas... 

Isfahan Zirconium Production Plant (ZPP) is one of the most important plants in the nuclear industry of Islamic Republic of Iran. The wastewater of this plant contains high values of Sodium, Chloride, Nitrate and low values of Calcium, Magnesium, Zinc and Zirconium ions. Its release has been banned by international and national law because of the dangers and toxicity of its ions for the environment and living organisms. Therefore, its refinement as a compensation of Iran’s water resources in agriculture and drinking water has received a major consideration. Among the common methods to removal of these ions, membrane process method is selected due to it's major benefits such as not producing... 

Recently, biopolymers such as alginate, cellulose, chitosan, gelatine, starch and wool have been used as supports for catalytic applications. Several interesting features of the biopolymers for example, bio-degradable, environmentally safe, high sorption capacity, physical and chemical versatility make them attractive to use as supports. This study, the four functionalized biopolymer-based composites were designed and synthesized as well as heterogeneous catalysts used in the synthesis of 1,2,3-triazoles, oxidation of alcohol, reduction of nitroarenes and carbon-carbon coupling reactions.A novel cellulose supported copper NHC complex has been prepared by the reaction of cellulose supported... 

Today, the pollution of heavy metals in wastewater and surface waters, which is a global environmental problem, has increased with the expansion of various industrial activities. Heavy metals cause serious health problems due to their accumulation in human and animal tissues. Thorium, is a radioactive element with an atomic number of 90 that is widely used in the optics, aerospace, metallurgy and chemical industries, in the manufacture of high-strength alloys, in UV photocells, and especially in the nuclear industry. The primary sources of radioactive wastewater include nuclear power plants, nuclear energy industry research centers, medical institutions, industrial production, universities,... 

Carbon nanostructures are of great importance in scientific and industrial research. Two case of the important two-dimensional carbon nanostructures are graphitic carbon nitride (g-C3N4) and graphene. In the first part of this work, adsorption of important heavy metal cations including Hg+2, Ag+, Cr+3, Pb+2, Cu+2, Ni+2, Cd+2, Tl+, Sb+3, Zn+2 and As+3 on the surface of (g-C3N4) was investigated by density functional theory (DFT). The main purpose of this theoretical study is to evaluate the ability of g-C3N4 to adsorb pollutant cations. The most prominent result of this work was the ability of g-C3N4 for effective adsorption of As+3 and Sb+3 ions from aqeous solutions. Also, another... 

To investigate the metallic cation (Ni and Pb) removal performance of the rice barn-obtained biochar which was modified by nitric acid and titanium nanoparticles (TiO2) adsorption tests were conducted in continuous and non-continuous systems. First section addressed the characterization of the synthesized sorbents using field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X ray spectroscopy (EDX) and sorption-desorption porosity analysis (BET). In the second section, the effect of different parameters such as pH, initial concentration of the metallic ions, temperature, time, sorbent content, ionic... 

Heavy metals such as lead, chromium, nickel are considered as environmental pollutants. These substances are highly toxic and dangerous to humans and other organisms at low concentrations and many problems are caused by them. Chromium belongs to the group of heavy and toxic metals. Form 6-valent chromium for humans is considered a definite carcinogen and also creates other problems. One common method of chromium removal is chemical precipitation which caused a large volume of waste. Other methods such as ion exchange, solvent extraction, reverse osmosis and biological methods are used to remove chromium. Adsorption is another effective method with very few disadvantages compared to other... 

This study focused on the tolerance of fungi strains including Aspergillus niger, Aspergillus foetidus and Penicillium for different metals (Ni, Co, Mo, V, Mn, Mg, Fe, W and Zn ). Then Aspergillus niger was exposed to mixture of Mo, V and Mn (at a mass ratio of 1:2:6 as approximately present in the spent refinery processing catalyst). The degree of tolerance was measured from the growth rate in the presence of various metals and compared to a control which contained no metals. Effect of type of strains, type of metal and metal concentration on adaptive tolerance of fungus was evaluated. Adaptation experiments with single metals showed Aspergillus niger tolerated up to 1000 mg/l Ni, Zn, 1500... 

The oilfields' wastewater, the water that is produced beside oil and is called ''Produced Water'', includes a large variety of pollutants. Heavy metals such as Lead, Manganese, Zinc and Barium and their compounds are some of the produced water's pollutants and because of their high stability they accumulate in life cycle. So a suitable and proper treatment is necessary. A combination of effectual and important parameters such as good adsorption, magnetic properties and low prices made Iron nanoparticles have a bright future in management of environmental pollutions. In this study Maghemite and Magnetite nanoparticles are used to remove heavy metals and effect of others factors such as pH,... 

One of the most important parts of bacteria growth is specific concentration of nutrients added. Although the trace amount of heavy metals are required for bacteria growth, after a threshold concentration they may cause damage or kill the bacteria. Scientifically speaking, all these trace nutrients should be consider as a profitable source of energy for bacteria growth. There are several studies throughout pondering whether the advantages of using heavy metals, such as Zn, outweigh the drawbacks. It has been proven that heavy metals, especially, zinc salt, can improve microbial growth up to a specific threshold concentration. In this study, two upward submerged aerated reactors, which had 12... 

The main objective of this research was to evaluate the application of a new strain of Brevundimonas naejangsanensis which is newly identified sulfate-reducing bacteria (SRB), in chromium(VI) removal in contaminated wastewater. A laboratory scale packed bed reactor (PBR) was fabricated and operated to study the bacteria’s feasibility on chromium(VI) reduction and removal. The reactor was packed with polyurethane foam cubes and operated under different feeding and operating conditions of HRT, COD/〖SO〗_4^(2-) ratio and influent chromium(VI) concentration. A maximum chromium removal of 94.6% was achieved in the PBR when operated at an HRT of 24 h with COD/〖SO〗_4^(2-) ratio of .70 and influent...