Sharif Digital Repository

Background: Water contamination by noxious heavy metals due to urbanization is a global environmental problem. Heavy metal ions pollution makes the water unsuitable for drinking and is also highly toxic to human beings and eco-system. The remediation of heavy metals is therefore very crucial. Methods: Adsorbents based on biopolymer and eco-friendly polymer composites have been developed and fabricated to remediate and remove heavy metals from the ecosystem. Results: In recent years biocomposites have been successful as cost-effective adsorbents for the remediation of various contaminants with their eco-friendly nature and sustainability. Conclusion: This review article gives an overview on... 

An eco-friendly, simple, and effective protocol is developed for the synthesis of various multisubstituted 2-aminothiophenes. In the presence of a catalytic amount of ZnO (5 mol), ketones or aldehydes, malononitrile and elemental sulfur were converted to the corresponding 2-aminothiophene derivatives in moderate to high yields (27%-70%) under solvent-free conditions at 100 °C. Zinc oxide as an efficient, readily available, and reusable catalyst, showed very good catalytic activity for the synthesis of 2-aminothiophene derivatives. Thus far, little research has been reported on the Gewald reaction under solvent-free conditions; to the best of our knowledge, this is the first time that it has... 

The ultimate goal of new food packaging technologies, in addition to maintaining the quality and safety of food for the consumer, is to consider environmental concerns and reduce its impacts. In this regard, one of the solutions is to use eco-friendly biopolymers instead of conventional petroleum-based polymers. However, the challenges of using biopolymers in the food packaging industry should be carefully evaluated, and techniques to eliminate or minimize their disadvantages should be investigated. Many studies have been conducted to improve the properties of biopolymer-based packaging materials to produce a favorable product for the food industry. This article reviews the structure of... 

In this research, a series of numerical simulations were conducted utilizing computational fluid dynamics (CFD) software in order to predict the heat transfer performance of queues nanofluids containing clove-treated graphene nanoplatelets (CGNPs) flowing in a horizontal stainless steel heated pipe. The GNPs were covalently functionalized with clove buds using free radical grafting reaction using an eco-friendly process. The advantage of this synthesis method was that it did not use hazardous acids, which are typically used in traditional treatment methods of carbon nanostructures. The thermo-physical properties of the aqueous nanofluids obtained experimentally were used as inputs for the... 

The catalytic activity of a mixture of ZnCl2: AlCl3 supported on silica gel was evaluated for the alkylation of phenols with benzyl alcohol, tret-butyl alcohol and styrene under microwave irradiation and solvent-free conditions. The catalyst preparation method, its characterization and reusability, were reported. The effect of the phenol to benzyl alcohol ratio and the time of reaction on the phenol conversion and distribution of products was investigated. A conversion percentage up to 97% was achieved when hydroquinone was used. A selective ortho- directed alkylation for phenol, α-naphthol and β-naphthol was observed. © Sharif University of Technology, December 2009  

Conventional additives used in drilling fluid may have detrimental short- and long-term impacts on the surrounding environment. The employment of biodegradable green material in drilling fluid as alternative additives will eliminate these harmful impacts. In this study, acorn shell powder is proposed as a novel biodegradable additive for application in drilling fluid. First, the acorn shell powder was prepared and then characterized in terms of chemical structure, particle size, and morphology. The acorn shell powder, with four different concentrations, was then introduced into a water-based fluid; its functionality in the fluid system was evaluated with respect to rheological and filtration... 

Rammed earth (RE) is an eco-friendly building material and has been capturing special attention among researchers. Many of the recently studied RE additives are extremely resource- and energy-consuming. On the other hand, the usage of fly ash (FA), which is a sustainable replacement for cement, has been scarcely investigated in RE construction. In this paper, an experimental investigation was performed on the physical and mechanical properties of RE materials stabilized with the combination of cement and alkali-activated FA. This scrutiny consists of density measurements, pulse velocity tests, unconfined compression tests, and direct shear tests. Additionally, the carbon dioxide emission and... 

Development of renewable energies is in parallel with improving high-performance energy storage devices, which can store maximum solar or wind energy and power. Herein, asymmetric energy storage systems are constructed from phosphorus-doped nickel sulfide (P-doped NiS) and biomass-derived humic acid (HA) as positive and negative electrodes, respectively. Initially, nickel sulfide (NiS) nanostructures are directly grown onto nickel foam (NF) via a hydrothermal step. P-doping into the NiS bulk is carried out through a simple hydrothermal process as well. Also, HA is activated via carbonization treatment (A-HA) for employing as the negative electrode's active material. The P-doped NiS-NF...