Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

Introduction to Spectroscopy

The objective of this investigation involved the green synthesis of Graphene Sand Hybrid (GSH) using the sustainable carbon source provided from the pyrolysis of low-quality dates; it was evaluated for use as a cost-effective reactive material in permeable reactive barrier (PRB) technology for remediating lead-Pb(II) and tetracycline-TC contaminated groundwater. The GSH was proven to be composed of graphene structures on the inorganic support material (sand). The experimental experiments of this study were done using batch and continuous mode. In the batch experiments, different factors were studied, and the sorption data were explained using the Langmuir and Freundlich isotherm models, whereas the sorption kinetic was ascertained through the use of the three kinetic models (pseudo-first, second-orders, and intraparticle diffusion). The results evidenced that the Langmuir and the pseudo-second-order models show a better fit for the experimental data, with a maximum adsorption capacity of 55.4 mg/g and 46.4 mg/g for Pb(II) and TC, respectively. The continuous mode was performed employing a series of column experiments. Besides, the COMSOL Multiphysics software was used to solve a numerical model that was advanced to simulate the equilibrium one-dimensional contaminant's conveyance. The results depicted that the GSH was an efficient material in PRB technology to remediate contaminated groundwater. 

Batch and continuous study of one-step sustainable green graphene sand hybrid synthesized from Date-syrup for remediation of contaminated groundwater

In this work, Graphene Glass Hybrid (GGH) was fabricated through pyrolysis by adopting a green method in which the sustainable carbon source used was low-quality-dates and the supporting material was glass waste (GW). The GGH was identified as a cost-effective and functional reactive material, suitable for use in permeable barrier technology to remediate (Pb) lead-and (TC) tetracycline-contaminated groundwater, via batch and continuous experiments. The GGH prepared showed macroporous structures that resembled 2-D graphene sheets, stacked on the inorganic glass support, capable of eliminating the Pb and TC from the aqueous medium. The GGH composite thus prepared was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) analysis, Raman spectroscopy , electron diffraction measurements, X-ray photoelectron spectroscopy, Energy-Dispersive X-ray (EDX), and measurements of the surface area. From the results, the Langmuir model was proven to give a better fit than the Freundlich model, for the sorption data; from the perspective of kinetics, the pseudo-second-order model fitted the experimental data better than the pseudo-first-order model. In order to assess the performance of the GGH reactive medium, in continuous mode, a series of column experiments were performed. To simulate the conduction of Pb and TC through the GGH reactive medium in one-dimensional equilibrium transport, a numerical model solved using the COMSOL Multiphysics 3.5a software was advanced. From the findings, the GGH was proven to be effective, eco-friendly, and economically reactive in PRB , for the remediation of Pb- and TC-contaminated groundwater. 

Green approach for the synthesis of graphene glass hybrid as a reactive barrier for remediation of groundwater contaminated with lead and tetracycline

used as a nanofiller. The methods used to synthesis bentonite nanoparticles are ball mill and co-precipitation and modification with surfactant cetyltrimethylammonium bromide (CTAB). Likewise, the OPBA synthesis process with the ball mill process and co-precipitation. Characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), FTIR and X-ray fluorescence (XRF). The results of characterization using XRD showed a decrease in particle size in bentonite-OPBA nanocomposites. The SEM results show uniformity of particle size in Bentonite-OPBA nanocomposite. Meanwhile, the FTIR results showed absorption peaks indicating bonding in the nanocomposite, confirmed by XRF results. The XRF results show the content of SiO2 and Al2O3 in the nanocomposite so that it can be applied as a nanofiller.

Analysis structure and morphology of bentonite-opba nanocomposites as nanofillers


 The objective of this investigation involved the green synthesis of Graphene Sand Hybrid (GSH) with the sustainable carbon source provided from the pyrolysis of low-quality dates; it was evaluated for its use in permeable reactive barrier (PRB) technology for treating lead- (Pb) and tetracycline- (TC) contaminated groundwater, as a cost effective and highly reactive material. The GSH thus produced was evaluated by testing its properties through a variety of testing procedures. From these tests the GSHs prepared were proven to be composed of graphene structures on the inorganic sand, with the capacity to treat simulated contaminated groundwater. The experimental experiments of this study were done using batch and continuous mode. In the batch experiments, different factors that affect the sorption process were studied and the sorption data were explained using the Langmuir and Freundlich isotherm models, whereas the kinetic process of sorption was ascertained through the use of the three kinetic models (pseudo first- and second-orders and intra particle diffusion). From the results it was evident that the Langmuir model shows a good fit for the sorption data, better than the Freundlich isotherm model does, and the pseudo second-order model shows a better fit for the kinetic data than does the first-order model. The continuous mode was performed employing a series of column experiments. Besides, using the COMSOL Multiphysics software, a solved numerical model was advanced for simulation of the one-dimensional equilibrium conveyance. The results depicted that the GSH can be effective and economically reactive material in PRB.

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Fabrication of Graphene Sand Hybrid Using Green Method for Remediation of Lead and Tetracycline Contaminated Groundwater

Modified bentonite has been used as effective sorbent material for the removal of acidic dye (methyl orange) from aqueous solution in batch system. The natural bentonite has been modified using cationic surfactant (cetyltrimethyl ammonium bromide) in order to obtain an efficient sorbent through converting the properties of bentonite from hydrophilic to organophilic. The characteristics of the natural and modified bentonite were examined through several analyses such as Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Surface area. The batch study was provided the maximum dye removal efficiency of 88.75 % with a sorption capacity of 555.56 mg/g at specified conditions (150 min, pH= 2, 250 rpm, and 0.5 g/100 ml). The-results-showed that with the Freundlich isotherm model the sorption data was accurately described with (R2≥0.94) in comparison with the Langmuir model under the studied conditions. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

Removal of Acidic Dye from Aqueous Solution Using Surfactant Modified Bentonite (Organoclay): Batch and Kinetic Study

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

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Saraa Muwafaq Ibrahim

Papers

Removal of Acidic Dye from Aqueous Solution Using Surfactant Modified Bentonite (Organoclay): Batch and Kinetic Study

Using of modified-bentonite as low-cost sorbent for removal of methylene blue dye from aqueous solution