In the present study, an organic wastewater industrial pollutant such as a phenol was removed by the improved modified adsorbents: NH3-activated carbon, and NaOH-activated. When the activated carbon ACDK was recovered from agricultural waste Date Kernel and prepared via pyrolysis and thermal activation at 850 ° C. The modification of the activated carbon surface ACDK was ready chemically with the impregnation in the 10wt %   ammonia solution to obtain a modified adsorbent: NH3-ACDK, the impregnation of ACDK in 10 wt% Sodium Hydroxide solution for the second modified adsorbent: NaOH-ACDK. The modified functional samples were characterized by SEM, FT-IR and DRX, TGA-DSC. The results established that phenol molecules were favorable for adsorption on the nitrogen group and hydroxide group of activated carbon at pH 4, solution temperature (28°C), and contact time (60-100 minutes). The adsorption kinetics of phenol on the modified adsorbents were better adapted to the pseudo-second-order adsorption model with (R² = 0.985) for NH3-ACDK, (R² = 0.980) for NaOH-ACDK. The adsorption isotherm follows the Langmuir design and is fitted well compared to Freundlich models with (R2= 0,999) for NaOH-ACDK, Langmuir, and Freundlich isotherms models fit the experimental equilibrium data for NH3-ACDK) with correlation coefficient (R²≥ 0,989). The removal percentage of phenol on NH3-ACDK, and NaOH-ACDK was 97,6 % and 70,3%, respectively.

This paper presents a comparative study of the surface chemistry, texture, and adsorption properties of activated carbon and silicon carbide nanoparticles loaded on activated carbon. Activated carbon has been prepared from the pulp of oak cups using a chemical activation method, with silicon carbide nanoparticles used to modify the surface of activated carbon. Scanning electron microscopy, Fourier transform infrared spectroscopy, N2 adsorption-desorption isotherms, and points of zero charge determination are the methods that have been employed to determine the physicochemical properties of raw material, activated carbon, and silicon carbide nanoparticles loaded on activated carbon, respectively. Results demonstrated that the activated carbon is composed mainly of micropores, with a Brunauer–Emmett–Teller surface area of 1253.92 (m2/g), and that the attachment of silicon carbide nanoparticles changed the surface properties of activated carbon. The adsorption equilibrium of two azo dyes on activated carbon and silicon carbide nanoparticles loaded on activated carbon was investigated using the Langmuir, Freundlich, and Temkin isotherms. Experimental data were fitted to conventional kinetic models, including the pseudo-first-order, second-order, Elovich, and intraparticle diffusion models. For all adsorbents, the removal process follows the pseudo-second-order kinetic model. Equilibrium adsorption parameters reveal that a higher adsorption capacity was found for silicon carbide nanoparticles loaded on activated carbon. These features indicate that silicon carbide nanoparticle-activated carbon is a promising and new adsorbent for the removal of acidic dyes during wastewater treatment.

The powdered activated carbon (AC) supported by carbonaceous nano-adsorbents were examined to remove hexavalent chromium [Cr (VI)] from aqueous solution The adsorption behaviour of micro-level concentration of Cr (VI) on those nano-adsorbents was investigated as a function of the experimental conditions such as the contact time, the pH, the dosage of adsorbent, and the initial concentration of Cr (VI). The structural characterization of the adsorbents was accomplished by Fourier transform infrared spectroscopy and scanning electron microscopy.Adsorption isotherms including Freundlich and Langmuir have been applied to study the equilibrium of the adsorption behaviour and identify the adsorption capacity of the activated carbon-functionalized multiwalled carbon nanotubes (AC/f-MWCNTs) and activated carbon-functionalized carbon nanospheres (AC/f-CNSs). Langmuir isotherm model showed that the adsorption process was monolayer type under working with an adsorption capacity of 113.29 and 105.48 mg/g, respectively, for AC/f-MWCNTs and (AC/f-CNSs).

Background: Today, advances in different areas of science and technology along with their application in industries have led to an increase in dangerous pollutants which can resist biodegradation. Volatile organic compounds (VOCs) are regarded as important factors of air pollution in closed environments. Xylene is one of these compounds which is produced in mass quantities and widely used in industries, therefore, the removal of this compound is necessary. One of the available technologies for removing this compound is photocatalytic degradation. The present study aimed to determine the efficiency of photocatalytic removal of xylene as a pollutant in air using TiO2-ZnO nanoparticles and TiO2-ZnO composite coated on activated carbon under ultraviolet radiation. Methods: In this experimental study, after coating of the nanoparticles on activated carbon, the produced catalysts with a specific surface area were characterized using Brunauer-Emmett-Teller (BET) surface area and porosity analysis, scanning electron microscope (SEM), and the type and percentage of the main elements present in the bed were determined using energy dispersive x-ray spectroscopy (EDS). The tests were carried out at laboratory scale and ambient temperature. In order to produce polluted air containing 100 ppm xylene vapor at a specific flow rate and concentration, a dynamic concentrator system was used. The removal of xylene was investigated under continuous flow mode. Results: The results of the specific surface area using BET analysis and SEM images showed that nanoparticles were well coated on activated carbon. According to the results of the photocatalytic removal, the efficiencies of photocatalytic removal of xylene by AC/ZnO 5%, AC/TiO2 15%, and AC/3TiO2/1ZnO were 80. 1, 89, and 95. 1%, respectively. Conclusion: According to the results, the use of ZnO-TiO2 nanocomposite on activated carbon can be an appropriate method for the photocatalytic removal of xylene from polluted air.

Currently, carbon quantum dots have attracted considerable attention due to their unique properties and desirable advantages. High crystallinity, water solubility, good dispersibility, small size, low toxicity, inexpensive raw materials, high chemical stability, environmental compatibility, low cost, stability under light, desirable charge transfer with advanced electronic conductivity, as well as specific thermal and mechanical properties are some of these features. Carbon quantum dots have various applications in different fields. Fabrication of precise chemical and biological sensors, bioimaging, solar cells, drug tracking, nanomedicine, light-emitting diodes (LEDs), and electrocatalysts are some of these applications. Biological sensors based on carbon quantum dots are capable of detecting various metal ions, acids, proteins, biotin, polypeptides, DNA and miRNA, water pollutants, hematin, drugs, vitamins, and other chemicals. In the present study, the properties of carbon quantum dots and some of their fabrication and applications methods have been addressed. In continuation of the paper, the effect of carbon quantum dots on important factors in plants such as growth and development, photosynthesis, absorption and transportation of substances, resistance to biotic and abiotic stresses, as well as their application in agriculture has been investigated.