Esraa M. Bakhsh

Anti-bacterial PES-cellulose composite spheres: dual character toward extraction and catalytic reduction of nitrophenol

Polyethersulfone (PES) based hybrid adsorbents were used for the removal of different phenols from aqueous solutions, which are categorized as major aquatic organic pollutants. In an effort to develop adsorbents with high surface area, PES, PES-silica (PES-SiO2), PES-carbon black (PES-CB) and PES-cellulose acetate-CB (PES-CA-CB) were prepared in the form of spheres and characterized by using FESEM, TEM, EDS, XRD, FTIR, and TGA. All the hybrid spheres were selective toward adsorption of 4-nitrophenol (4-NP) and among different hybrid spheres, PES-CA-CB spheres possessed high affinity and competent selectivity toward 4-NP. Therefore, different adsorption parameters have been optimized for PES-CA-CB spheres. The adsorption uptake of 4-NP onto PES-CA-CB spheres was highly dependent on pH and concentration of 4-NP. The highest adsorption was recognized at a pH around 6. The adsorption isotherm of 4-nitrophenol on PES-CA-CB obeyed the Langmuir model with an adsorption capacity of 128.79 mg g−1. Further, all hybrid spheres were utilized as supporting materials for Cu nanoparticles. Hybrid spheres supported Cu nanoparticles were applied for the catalytic reduction of 4-NP. Among all the hybrid spheres supported Cu nanoparticles, PES-CA-CB spheres supported Cu (Cu@PES-CA-CBspheres) nanoparticles exhibited high catalytic activity. Finally, Cu@PES-CA-CBspheres showed excellent antibacterial activity compared to all the hybrid spheres and hybrid spheres supporting Cu nanoparticles. All these adsorbents and catalysts can be prepared by a very simple method, are easily recovered by just removing the pellet from the solution and can be used several times.

Poly(propylene carbonate)/exfoliated graphite nanocomposites: Selective adsorbent for the extraction and detection of gold(III)

In this study, poly(propylene carbonate) (PPC) and exfoliated graphite (PPC–EG) composites were prepared by the solution blending method and their selective extraction and detection of gold(III) were investigated. Specifically, a new effective adsorbent was developed for a selective extraction and determination of gold(III) by use of inductively coupled plasma optical emission spectrometry. The selectivity of PPC (PPC–EG 0.5, PPC–EG 1, PPC–EG 2, PPC–EG 3 and PPC–EG 5) was investigated toward several metal ions, including Au(III), Cd(II), Co(II), Cu(II), Hg(II), Pb(II), Pd(II) and Zn(II). Based on selectivity and pH studies, Au(III) was the most quantitatively adsorbed on PPC–EG 0.5 phase at pH 2, indicating that PPC–EG 0.5 was the most selective toward Au(III) among other metal ions. The adsorption isotherm followed the Langmuir model with adsorption capacity of 157.61 mg g−1 of PPC–EG 0.5 for Au(III), which was in agreement with experimental data of adsorption isotherm study. The kinetic of adsorption for Au(III) was investigated by a pseudo-first- and second-order models. Results of kinetic models displayed that the adsorption of Au(III) on the PPC–EG 0.5 phase obeyed a pseudo-second-order kinetic model. In addition, results of thermodynamic investigation demonstrated that the adsorption mechanism of PPC–EG 0.5 toward Au(III) was a general spontaneous process and favourable.

Performance of cellulose acetate-ferric oxide nanocomposite supported metal catalysts toward the reduction of environmental pollutants

Water contamination by toxic compounds has become one of the most serious problems worldwide. Catalytic reduction using metal nanoparticles offer opportunities for environmental benefits. In this study, cellulose acetate-ferric oxide nanocomposite (CA/Fe2O3) was prepared and used as support for metal nanoparticles. After adsorption of Ag, Cu or Ni ions from aqueous solutions, metal ions associated with CA/Fe2O3 were treated with sodium borohydride to prepare Ag, Cu and Ni nanoparticles loaded CA/Fe2O3. The CA/Fe2O3 supported Ag, Cu or Ni nanoparticles was evaluated as a catalyst for pollutants degradation. Silver nanoparticles (Ag@CA/Fe2O3) exhibit remarkable decomposition for methyl orange dye and p-nitrophenol in short time. The rate constant for methyl orange and p-nitrophenol were 8.58×10-3 and 4.77×10-3s-1, respectively. Besides the good catalytic activities of Ag@CA/Fe2O3, the catalyst could be easily recovered from the reaction medium by pulling the catalyst after completion of the reduction reaction. The recovered catalyst can be recycled several times if their exposure time to air was minimal.

Cellulose acetate-iron oxide nanocomposites for trace detection of fluorene from water samples by solid-phase extraction technique

ABSTRACT In this study, cellulose acetate (CA)/iron oxide nanocomposites (NC1 and NC2) were synthesized and utilized as extractors for the selective separation of fluorene from aqueous samples. The selectivity of nanocomposites to different organic compounds was assessed. Based on the results, fluorene was the most quantitatively adsorbed on NC2. Batch method was performed by varying the initial fluorene concentrations and contact time. Langmuir and Freundlich isotherms were used for modeling the experimental data and were best correlated by the Langmuir model. Adsorption data were also followed the pseudo-second-order kinetic model. Finally, validation of the developed method was achieved for fluorene determination in real water samples.

Synthesis and characterization of metal nanoparticles templated chitosan-SiO 2 catalyst for the reduction of nitrophenols and dyes

Different metal nanoparticles (MNPs) templated on chitosan-silica (CH-SiO2) nanocomposite fiber were prepared via simple and fast method of the metal ions uptake by fiber and their subseqent reduction using strong reducing agent. The performance difference of CH-SiO2 templated with Cu, Co, Ag and Ni nanoparticles for both reduction of 4-nitroaniline (4-NA) and decolorization of congo red (CR) was investigated. The Cu nanoparticles loaded CH-SiO2 (Cu/CH-SiO2), showed high catalytic efficiencies in the reduction of 4-NA and CR, as compared to other loaded MNP fibers. The apparent rate constants of 6.17 × 10-3 s-1 and 1.68 × 10-2 s-1 and turnover frequencies (TOF) of 4.693 h-1 and 3.965 h-1 were observed for the reduction of 4-NA and CR, respectively. In addition, the catalytic activity of Cu/CH-SiO2 catalyst was also examined and found efficient in the reduction of nitrophenols (2-NP, 3-NP and 4-NP), and other dyes. Thus, Cu/CH-SiO2 with excellent catalytic activity can also be employed for other applications.

Assessment of cellulose acetate/manganese oxide thin film as adsorbent for selective extraction of flavone

The present study depicts the efficiency of cellulose acetate/manganese oxide thin films as adsorbents for selective extraction and detection of flavone in environmental waters. The selectivity of thin films (CA/Mn-1 and CA/Mn-2) was evaluated towards several organic compounds. Based on selectivity study results, CA/Mn-2 thin film was the most selective towards flavone among other compounds. In addition, the effect of other parameters such as contact time and initial concentration of flavone was investigated to optimize adsorption conditions. The adsorption capacity of flavone was experimentally obtained as

Selective adsorption of 4-chlorophenol based on silica-ionic liquid composite developed by sol-gel process

57.96\hbox { mg}\hbox { g}^{-1}

Cerium oxide‑cadmium oxide nanomaterial as efficient extractant for yttrium ions

57.96mgg-1 and theoretically calculated from Langmuir equation as