اطهر انتظاری

Activated carbon is a most common adsorbent. By emerging of new technologies, the activated carbon production methods need to be improved. The aim of this study was producing powdered activated carbon from Peganum Harmala seed under ultrasound waves for activation and its application for chromium removal from aqueous solutions.
This experimental study was conducted in a batch reactor. The Peganum Harmala seeds were used for activated carbon production and Ultrasonic waves were used to activation. The BET test was done in order to determine of the specific surface area of produced activated carbon. The most important variables affecting the adsorption process were examined. For Cr(VI) determining UV/VIS Spectrophotometer T80 at a wavelength of 540 nm was used. Data analysis was performed by Excel software.
The BET test results showed that the specific surface area of produced ​​activated carbon is 442m2/g. The optimum pH of solution to adsorption process by both raw powder of Peganum Harmala seeds and produced powdered activated carbon adsorbents was equal 2. Adsorption data for both adsorbents were best fitted to the pseudo-second order kinetic and parameter of K2 for the produced powdered activated carbon was obtained two times more than K2 for raw powdered Peganum Harmala seed.
The results showed that ultrasound is very effective in activation of carbon and produced activated carbon have high adsorption rate and specific surface area, it and can be used as an appropriate adsorbent for removal of hexavalent chromium.

Because of the disadvantages of antibiotics in the ecosystem, it must remove before discharging wastewater containing them into the environment by an effective process. The aim of this study was cephalexin removal by local green montmorillonite loaded with TiO2 nanoparticles (TiO2/GLM) in the presence of potassium permanganate.
This experimental study was performed in batch. In this study, green montmorillonite found in the area of Ardabil sarcham used as base absorbent and to improve the efficiency of cephalexin removal stabilized TiO2 nanoparticles on it using potassium permanganate. Then, the most important variables affecting the process have been investigated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) tests used to investigate absorbent surface morphology and functional groups on the adsorbent respectively. The samples were analyzed by a spectrophotometer and data analysis was performed using Excel software.
SEM images showed that the absorbent surface has a high roughness and FTIR test showed change the functional groups because loading of TiO2 nanoparticles.the optimal condition was pH = 5, detention time= 60 min and adsorbent dose = 4 g/l for initial Cephalexin concentration of 25 mg/l. Also the results showed by decreasing temperature, removal efficiency was increased.
Due to the high efficiency of TiO2/GLM in the absorption of cephalexin as well as its morphology did not change after adsorption process, we can say that this adsorbent can be used as a cheap and efficient absorbent for the removal of cephalexin used

Because of toxical and hazardous properties of hexavalent chromium (Cr(VI)), its removal by an economical and efficient method is necessary. The use of activated carbon, as an adsorbent, is a common and effective method for hexavalent chromium removal. Thus the aim of this study was to produce granular and powdered activated carbon form Peganum Harmala and compare their chromium removal efficiency from synthetic wastewater.
This experimental study was carried out in a batch reactor in the laboratory. Peganum Harmala was used as an activated carbon production precursor and ultrasonic waves were used for carbon activation, and Brunauer–Emmett–Teller (BET) test was used for determination of specific surface area of activated carbon.. In this study the effect of pH, adsorbent dosage, initial chromium concentration, contact time,and mixing speed were investigated. The colorimetric method using UV/VIS Spectrometer T80 at a wavelength of 540 nm was used for chromium determination. Data analysis was performed by Excel software.
The BET test showed that the Granular and powdered activated carbon specific surface area were equal to 442 and 310 m2/g, respectively that indicates the activation process efficacy. The adsorption experiments showed that the optimum pH for Cr(VI) was equal to 2 for both adsorbents and powdered activated carbon had more removal efficiency than its granular form. The kinetic tesults of the reactions indicated that both adsorbents followed pseudo-second order kinetic in the absorbtion process.
Comparing specific surface area and chromium adsorption capacity shows that powdered activated carbon is a more efficient and economical adsorbent than the granular form.