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

Increasing amount of dyes in an ecosystem has propelled the search of various methods for dye removal. Amongst all the methods, adsorption occupies a prominent place in dye removal. Keeping this in mind, many adsorbents used for the removal of hazardous anionic azo dye Congo red (CR) from aqueous medium were reviewed by the authors. The main objectives behind this review article are to assemble the information on scattered adsorbents and enlighten the wide range of potentially effective adsorbents for CR removal. Thus, CR sorption by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites are surveyed and critically reviewed as well as their sorption capacities are also compared. This review also explores the grey areas of the adsorption performance of various adsorbents with reference to the effects of pH, contact time, initial dye concentration and adsorbent dosage. The equilibrium adsorption isotherm, kinetic and thermodynamic data of different adsorbents used for CR removal were also analysed. It is evident from a literature survey of more than 290 published papers that nanoparticle and nanocomposite adsorbents have demonstrated outstanding adsorption capabilities for CR. Graphical abstract ᅟ.

Adsorptive amputation of hazardous azo dye Congo red from wastewater: a critical review.

A comparative study about adsorption of natural palygorskite for methylene blue

This work deals with optimizing the conditions of pyrolysis and type of activator to upgrade the use of Casuarina equisetifolia fruit waste (CFW) as available and a potential precursor, in producti...

https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.171578

Optimizing the route for production of activated carbon from Casuarina equisetifolia fruit waste.

With an incubation time of about 5 days, early diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical to control the spread of the coronavirus disease 2019 (COVID-19) that killed more than 3 million people in its first 1.5 years. Here, we report on the modification of the dopant density and the phononic energy of antibody-coupled graphene when it interfaces with SARS-CoV-2 spike protein. This graphene chemeo-phononic system was able to detect SARS-CoV-2 spike protein at the limit of detection of ∼3.75 and ∼1 fg/mL in artificial saliva and phosphate-buffered saline, respectively. It also exhibited selectivity over proteins in saliva and MERS-CoV spike protein. Since the change in graphene phononics is monitored instead of the phononic signature of the analyte, this optical platform can be replicated for other COVID variants and specific-binding-based biodetection applications.

COVID-19 Spike Protein Induced Phononic Modification in Antibody-Coupled Graphene for Viral Detection Application.

Palygorskite clay has been investigated as low cost and ecofriendly adsorbent for the removal Basic Red 2(BR-2) from aqueous solution. Batch adsorption studies are carried out by observing effect of amount of adsorbent dose, contact time, pH, initial concentration of ( BR-2) and particle size of adsorbent on the adsorption capacity of the adsorbent were studied. Adsorption data fits the Langmuir and Freundlich adsorption isotherms. The calculated value of the Langmuir parameter for adsorption capacity of the dye over the adsorbent is 200mg/g adsorbent. This study shows that natural clay is successfully used to remove the Safranin-O dye from aqueous solutions as alternative to activated carbon.

https://archive.aessweb.com/index.php/5003/article/download/3546/5621

Adsorptive removal of dye from industrial effluents using natural Iraqi palygorskite clay as low-cost adsorbent.

In this study, natural Iraqi low- cost locally available clay (palygorskite) was studied for its potential use as an adsorbent for removal Congo red from aqueous solutions. Batch type experiments were conducted to study the effect of contact time, initial pH of the dye solution, initial dye concentration, adsorbent dosage, and particle size of adsorbent on adsorption capacity of Congo red. The adsorption occurred very fast initially and attains equilibrium within 60 min. When the effect of pH of solution dye on the yield adsorption has been carried in a range of 2-10, the adsorption obtained was nearly the same with very slightly effect of pH and it was reported that above 49.07 mg/g of Cong red by palygorskite clay occurred in the pH range 2 to 10. It was observed that the removal of Congo red increase with increasing initial dye concentration and adsorbent dose, but, adsorption capacity decrease with increasing adsorbent dose. The adsorption capacity increase with decreasing particle size of adsorbent. The equilibrium adsorption data were interpreted using Langmuir and Freundlich isotherm models. The obtained results revealed that the equilibrium data closely followed both models, but the Langmuir isotherm fitted the data better. The maximum adsorption capacity was found to be 99 mg/g at ambient temperature. Results indicate that Iraqi palygorskite clay could be employed as a low cost alternative to commercial activated carbon in wastewater treatment for the removal of colour and dyes.

/pdf/natural-iraqi-palygorskite-clay-as-low-cost-adsorbent-for-1m4u5h5lu3.pdf

Natural Iraqi palygorskite clay as low cost adsorbent for the treatment of dye containing industrial wastewater

Organic reagent, 4-(6-Bromo-2-Benzothiazolylazo) pyrogallol (4-Br-BTAP), was synthesized by coupling reaction of diazotized 2-amino-6-bromobenzothiazole with pyrogallol and purified using ethanol recrystallization method. Analysis and characterization of synthesized product were carried out using melting point, elementary analysis, IR and H¹-NMR. Dissociation constants of the organic reagent were calculated by spectrophotometric method. Absorption spectra of the 4-Br-BTAP in solvents of different polarities were investigated. Analytical application of 4-Br-BTAP was established with Cu (II) and Pd (II).

Synthesis and characterization of an organic reagent 4-(6-bromo-2-benzothiazolylazo) pyrogallol and its analytical application.

An experimental investigation on the removal of direct red 28 dye from wastewater by using rice-husk carbon as low cost adsorbent was carried out in a laboratory. Batch type experiments were conducted to study the influence of different parameters such as adsorbent dose, contact time, pH, initial concentration of dye and particle size of adsorbent. The removal data have been analyzed using Langmuir and Freundlich isotherm models. The adsorption process was in conformity demonstrated use of rice husk to obtain low cost adsorbent for dye removal from aqueous solution . Keywords: adsorption,  low cost adsorbent, isotherm, dye .

/pdf/adsorption-studies-of-direct-red-28-dye-onto-activated-1agngms89x.pdf

Adsorption Studies of Direct Red 28 Dye onto Activated Carbon Prepared from Low Cost Material

Virus has become a global pandemic because of the rapid spread and imaginative numbers of cases and deaths. It becomes the most important issue that brings the attention of not only scientists but also the press, international and publishing houses, etc. All the countries involved all researches and centres efforts to find a vaccine or treatment to control it to no avail. This study not only investigates and explores the interaction between three types of medicine (Hydroxychloroquine, Favipiravir, and Remdesivir), and the angiotensin-converting enzyme (ACE2) receptors but also comparing the results with the interaction between the active part of the virus (Spike protein (S1)) and the cell. All interactions and properties of all molecules have been studied theoretically using theoretical calculations and computational methods based on the density functional theory.
The results indicate that one of the drugs, which is Remdesivir could be an effective barrier inhibits the bind of the S1 with the human cell. This result could be interpreted in terms of the binding energy, since the binding energy of the Remdesivir molecule with the ACE2 equals -8.564 eV, while the binding energy of S1 is -5.666 eV.
This research also founds that the electrons transfer from the drug to the ACE2 is 10.873 e, which is higher than that of S1 (5.155e). In addition, the results exhibit the Hydroxychloroquine does not have enough capability to inhibit the binding process between the virus and the cell since its binding energy (-2.948 eV) and the number of electrons transfer (0.7670) are the lowest. Finally, the Fermi energies values of Remdesivir (-3.5 eV) and ACE2 (-3.4 eV) molecules are convergent. In the context of the elastic transport, this predication is an important result since it interprets the large number of electrons that have been transferred from Remdesivir to ACE2 molecule, as shown in Figure 3 and Table 2, and this introduces the Remdesivir as a promising drug.

/pdf/the-promising-barrier-theoretical-investigation-37n1nb5unf.pdf

Dakhil Nassir Taha

Papers

Adsorptive removal of dye from industrial effluents using natural Iraqi palygorskite clay as low-cost adsorbent.

Natural Iraqi palygorskite clay as low cost adsorbent for the treatment of dye containing industrial wastewater

Synthesis and characterization of an organic reagent 4-(6-bromo-2-benzothiazolylazo) pyrogallol and its analytical application.

Adsorption Studies of Direct Red 28 Dye onto Activated Carbon Prepared from Low Cost Material

The promising barrier: Theoretical investigation