The effective treatment of dye-containing simulated wastewater by using the cement kiln dust as an industrial waste adsorbent.

This study compares the adsorption behavior of both Methylene Blue (MB) and Congo Red (CR) dyes on the surfaces of cement kiln dust (CKD) powder from the experimentally simulated wastewater solution. The cement kiln dust powder was characterized using X-ray Fluorescence (XRF), X-ray diffraction (XRD), N2 adsorption-desorption Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) tests. The adsorption for such dyes was studied under varying mixing contact times, temperatures, and pH as well as various initial concentrations of both dyes and adsorbent using the batch mode experiments. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were applied, and the results revealed that the pseudo-second-order fitted well to the kinetic data. Thermodynamic parameters stated that the adsorption process was endothermic. Studying Linear and nonlinear forms of Langmuir and Freundlich's adsorption isotherms revealed that the adsorption process was followed by both homogeneous mono-layer and heterogeneous multilayer coverage on the active sites of cement kiln dust particles. The data showed that the adsorption capacities of the methylene blue and Congo red dyes were 58.43 and 123.42 mg/g, respectively and cement kiln dust is an adsorbent with little cost for the treatment of wastewater.

Enhanced Coating Protection of C-Steel Using Polystyrene Clay Nanocomposite Impregnated with Inhibitors.

Polymer-Clay Nanocomposite (PCN) coatings were prepared using the solution intercalation method. The raw Khulays clay was treated with NaCl to produce sodium clay (NaC). Thereafter, Cetyl Pyridinium Chloride (CPC) was used to convert NaC into the organic clay form (OC). PCN was prepared by adding polystyrene as the matrix to different weights of OC to prepare 1 wt.% and 3 wt.% PCN. To enhance the coating protection of C-steel in NaCl solution, PCN coatings were added to microcapsules loaded with some corrosion inhibitors PCN (MC). The microcapsules are prepared by the encapsulation of rare-earth metal Ce+3 ions and Isobutyl silanol into polystyrene via the Double Emulsion Solvent Evaporation (DESE) technique. Characterization techniques such as FTIR, X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM) were employed. FTIR confirmed the success of the preparation, while XRD and TEM revealed an intercalated structure of 1 wt.% PCN while 3 wt.% PCN has a fully exfoliated structure. Electrochemical Impedance Spectroscopy (EIS), Electrochemical Frequency Modulation (EFM), and Potentiodynamic Polarization showed an enhanced protection efficiency of PCN (MC) coatings. The results demonstrated that the corrosion resistance (RCorr) of 3% PCN (MC) coating was higher than all the formulations. These PCN (MC) coatings may provide corrosion protection for C-steel pipes in many industrial applications.

Removal of ciprofloxacin from simulated wastewater by pomegranate peels.

The adsorption of Ciprofloxacin (CPX) from aqueous solution by Pomegranate peels (POP) was investigated in a batch process. The influence of time (5-60 min) and CPX concentration (100-10,000 mg/L) on the adsorption ability of POP was studied. The POP was characterized by FTIR, scanning electron microscopy (SEM), and Zeta sizer. The kinetic of adsorption was analyzed by the pseudo-first-order and the pseudo-second-order kinetic equations using non-linear regression analysis. As well as non-linear regression analysis of Langmuir and Freundlich models were applied to specify the best non-linear curves, fitted to experimental data and estimate isotherm parameters. In order to assess the best-fit kinetic model or adsorption isotherm, three error analysis methods were used to evaluate the result of adsorption process, namely the sum of the squares of the errors (SSE), residual root mean square error (RMSE), and chi-square (χ2). On the basis of low three error analysis and high correlation (R2) of determination, it can be concluded that both the non-linear form of pseudo-second-order kinetic model and non-linear form of Langmuir are best suited to explain the adsorption of CPX onto POP. The maximum adsorption capacity for pomegranate peel as calculated by non-linear Langmuir curve was much higher than in previous work (999 mg/g) at natural pH (4-5) and 25 °C. The high adsorption capacity of POP makes them very low-cost and effective adsorbent materials for CPX from aqueous solution.