Manal Fawzy

From graphite oxide to highly water dispersible functionalized graphene by single step plant extract-induced deoxygenation†

We report a single step facile synthesis of highly water dispersible functionalized graphene nanosheets by plant extract-induced deoxygenation of graphite oxide (GO). The results of various characterizations reveal that the properties of such plant extract-converted graphene nanosheets (PCGN) are comparable to chemically converted graphene nanosheets (CCG). These results open a green route to the emerging graphene-based technologies.

Phytosynthesis of silver–reduced graphene oxide (Ag–RGO) nanocomposite with an enhanced antibacterial effect using Potamogeton pectinatus extract

A new green synthesis method for the preparation of a silver–reduced graphene oxide (Ag–RGO) nanocomposite using Potamogeton pectinatus (Po) plant extract is introduced. The size, morphology and crystallinity of the as-prepared nanomaterials were studied with an explanation for the role of Po in the synthesis. A preliminary antibacterial experiment was developed to ensure the enhanced antibacterial effect of the Ag–RGO nanocomposite. The antibacterial measurements were done using the colony counting method. The results indicated that the majority of the silver nanoparticles “AgNPs” were formed in a spherical shape with small sizes ranging from 11 to 20 nm. IR spectroscopy results indicated the role of amine and hydroxyl groups from Po in the reduction and capping processes. The preliminary antibacterial examination ensured the enhanced antibacterial effect of the Ag–RGO nanocomposite.

Biosorption of Cr(VI) from aqueous solution using agricultural wastes, with artificial intelligence approach

ABSTRACT Removal of Cr(VI) from aqueous solution by date-palm-leaves (DPL) and broad-bean-shoots (BBS) was investigated. FTIR, SEM, and EDAX showed that DPL has higher ability for ion-exchange to remove Cr(VI). Langmuir and Freundlich adsorption isotherms and kinetics revealed that DPL exhibited higher biosorption capacity. At Cr(VI) 100 mg/L, biosorbent-dose 5 g/L and 60 min contact-time, maximum Cr(VI) removal for DPL (98%) and BBS (95%) was achieved at pH 2 and 1, respectively. Adaptive-neuro fuzzy inference system determined the most important factor affecting Cr(VI) removal. The model indicated that DPL is more tolerant to pH levels, while BBS is a pH-sensitive adsorbent.

Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass

ABSTRACT Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L−1, initial Cd(II) 50 mg L−1, and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated.

Optimization of Cadmium (CD(2+)) removal from aqueous solutions by novel biosorbent.

ABSTRACT In this research, dead leaves of a common ornamental plant, Dracaena draca known also as dragon tree was used as a biosorbent for the removal of Cadmium (Cd2+) from aqueous solutions using a full 23 factorial experimental design. Three factors were investigated at two different levels, metal ion concentration (X = 10 and 100 ppm), hydrogen ion concentration (Ph = 2 and 7) and biomass dose (BD = 0.1 and 0.5g). Experiments were carried out in duplicates with 50 ml of Cd2+ solutions at room temperature. When comparing observed values (experimental) with calculated values (model), they were set closely together that allowed suggesting a normal distribution where (R2 = 0.9938). A characterization of the biosorbent was done by pHzpc and SEM-EDAX. Results also showed that the most significant effect for Cd2+ biosorption was ascribed to (X). The interaction effects of (pH BD) and (X pH) were found to have significant influence on Cd2+ removal efficiency. The highest Cd2+ removal percentage attained by 79.60% at X = 10 ppm, pH = 7 and BD = 0.5g. The reusability of the biosorbent was tested in three desorption cycles and the regeneration efficiency was above 99.7%.

Bio-based Methods for Wastewater Treatment: Green Sorbents

Due to their high cost and environmental impact, conventional treatment methodology of heavy metals polluted waters usually did not receive public acceptance. Recently, phytoremediation is considered as a cheaper and eco-friendly alternative treatment method. Phytoremediation includes two uptake processes: biosorption and bioaccumulation. This chapter elaborates the advantages and disadvantages of these two processes. A brief description of different environmental factors affecting biosorption isotherm, equilibrium, and kinetic models are also provided. Moreover, factors affecting biosorption process are discussed and the merit of using factorial experimental design in the optimization of biosorption process and reducing the number of experimental runs were also highlighted. A brief account of quality control and assurance for biosorption experiments are provided.

Statistical Methodology for Cadmium (Cd(II)) Removal from Wastewater by Different Plant Biomasses

The combined effects of metal ion concentration (X), hydrogen ion concentration (pH) and biomass dose (BD), on the biosorption of Cadmium Cd(II) were investigated. Two different plant biomasses; rice straw (Oryza sativa) and dragon tree leaves (Dracaena draca) were studied. The optimum conditions were found at (X)=10 ppm, (pH)=7 and (BD)=0.5 g. Under these conditions, desirability values of 0.996 and 0.997 for rice straw and dragon tree leaves were obtained, showing that the calculated model may represent the experimental model and give the desired conditions. The samples before and after biosorption experiments were characterized by Energy Dispersive X-Ray Spectroscopy.

Regression model, artificial neural network, and cost estimation for biosorption of Ni(II)-ions from aqueous solutions by Potamogeton pectinatus

ABSTRACT This study investigated the application of Potamogeton pectinatus for Ni(II)-ions biosorption from aqueous solutions. FTIR spectra showed that the functional groups of –OH, C–H, –C = O, and –COO– could form an organometallic complex with Ni(II)-ions on the biomaterial surface. SEM/EDX analysis indicated that the voids on the biosorbent surface were blocked due to Ni(II)-ions uptake via an ion exchange mechanism. For Ni(II)-ions of 50 mg/L, the adsorption efficiency recorded 63.4% at pH: 5, biosorbent dosage: 10 g/L, and particle-diameter: 0.125–0.25 mm within 180 minutes. A quadratic model depicted that the plot of removal efficiency against pH or contact time caused quadratic-linear concave up curves, whereas the curve of initial Ni(II)-ions was quadratic-linear convex down. Artificial neural network with a structure of 5 – 6 – 1 was able to predict the adsorption efficiency (R2: 0.967). The relative importance of inputs was: initial Ni(II)-ions > pH > contact time > biosorbent dosage > particle-size. Freundlich isotherm described well the adsorption mechanism (R2: 0.974), which indicated a multilayer adsorption onto energetically heterogeneous surfaces. The net cost of using P. pectinatus for the removal of Ni(II)-ions (4.25 ± 1.26 mg/L) from real industrial effluents within 30 minutes was 3.4

Heavy metal biomonitoring and phytoremediation potentialities of aquatic macrophytes in River Nile

USD/m3.