Mohaned Hammad

Bio: Mohaned Hammad is an academic researcher from University of Duisburg-Essen. The author has contributed to research in topics: Specific surface area & Nanoparticle. The author has an hindex of 2, co-authored 3 publications receiving 17 citations.

Large-scale synthesis of iron oxide/graphene hybrid materials as highly efficient photo-Fenton catalyst for water remediation

Abstract: The Photo-Fenton reaction is an advanced oxidation process to break down organic pollutants in aqueous systems. Moreover, the scalable synthesis and engineering of stable catalysts with a high specific surface area is extremely important for the practical application of the Photo-Fenton process. In the current study, we developed a low-cost method for large-scale production of iron oxide/graphene nanostructures with a controllable graphene loading for the photo-Fenton reaction. Under optimal condition, high efficiencies of degradation (>99%) of methylene blue, rhodamine B, acid orange 7, and phenol at a concentration (60 mg/mL) were reached in 60 min under UV-A irradiation (1.6 mW/cm2) with mineralization of 72, 77, 82, and 48%, respectively. More importantly, the iron oxide/graphene nanocomposites exhibited good stability over a wide range of pH (from 3 to 9) and can be magnetically separated from the solution and repeatedly used with consistent photocatalytic performance. This enhanced removal efficiency of the iron oxide/graphene nanostructure compared to iron oxide nanoparticles is attributed to the accelerated transfer of photo-generated electrons between iron oxide and graphene and its relatively large surface area. The results demonstrate that the iron oxide/graphene system could be potentially utilized for many environmental treatment processes.

Synthesis and characterization of magnetic nanoparticles, and their applications in wastewater treatment: A review

Abstract: The sustainable growth of any society is in direct proportion with developing novel methods and technologies for the management of its environmental quality. The use of Magnetic Nanoparticles (MNPs) has emerged as an efficient tool for remediation of wastewater owing to its intrinsic qualities including size, surface effect, quantum effect, etc. These intrinsic properties of MNPs have diversified their application in managing the qualitative stress on water resources. The present review aims to assess the use of MNPs in removing organic and inorganic contaminants from wastewater. Insights into various synthesis methods and their effects on contaminant removal are also presented. It is reported that MNPs provide target specificity and cost-effectiveness as compared to conventional treatment methods. Moreover, the biological synthesis of MNPs is proven to be eco-friendly and aids in sustainable development. Nearly 100% removal of various types of contaminants such as pharmaceuticals and personal care products, dyes, pesticides, heavy metals, etc. can be achieved through MNPs. Some MNPs have shown a magnetic saturation reaching up to 70 emu/g, and recycling up to 5 cycles with >95% removal efficiency. High pollutant removal efficiency (>98%) can also be achieved in a short time (within 5 min) by MNPs. It is noteworthy that, nanosorption along with the redox reactions are the most frequently used and efficient mechanisms of contaminant removal from wastewater samples.

Ionic Cross-Linking Fabrication of Chitosan-Based Beads Modified with FeO and TiO2 Nanoparticles: Adsorption Mechanism toward Naphthalene Removal in Seawater from Cartagena Bay Area.

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are complex molecules produced by the thermal decomposition of organic matter in anthropogenic activities. Novel composites with enhanced physicochemical properties aim to overcome limitations such as adsorption capacity, affinity, and stability for PAHs adsorption. Composites based on chitosan are promising due to the good biocompatibility and adsorption properties. This study focuses on the facile preparation of chitosan beads modified with iron oxide (FeO) and titanium dioxide (TiO2) nanoparticles via ionic cross-linking (Ch-FeO/TiO2). FeO and TiO2 were synthesized performing co-precipitation and green chemistry methods, respectively. The characterization evidenced the formation of Ch-FeO/TiO2 with good crystallinity, excellent thermal stability, and superparamagnetic response, attributed to the presence of FeO and TiO2 nanoparticles. High thermal stability up to 270 °C was related to the cross-linked chitosan network. The enhanced adsorption mechanism of Ch-FeO/TiO2 was determined by removing naphthalene from water and seawater samples. The Ch-FeO/TiO2 showed a higher adsorption capacity of 33.1 mg/g compared to 29.8 mg/g of the unmodified chitosan (un-Ch) beads. This is due to the higher functional surface area of 27.13 m2/g, compared to that of 0.708 m2/g for un-Ch. We found a rapid adsorption rate of 240 min and the maximum adsorption capacity of 149.3 mg/g for Ch-FeO/TiO2. A large number of actives sites allows for increasing the naphthalene molecules interaction. Adsorption in seawater samples from Cartagena Bay (Colombia) exhibits an outstanding efficiency of up to 90%. These results suggest a promising, cheap, and environmentally friendly composite for remediation of water sources contaminated with complex compounds.