Natural processes and industrial activities can cause CHROMIUM to enter water resources. CHROMIUM in water enters food chain and causes diseases like cancer, skin dermatitis, and other health problems. In this work, cellulose adsorbent, Kraft paper, was used to remove CHROMIUM (VI) from water. The ash of the cellulose adsorbent was 2%, and its specific surface area was 3. 6 m2/g according to the BJH isotherm adsorption branch. Cellulose adsorbent was also characterized by FTIR, SEM, and EDX methods. The effects of pH were investigated in Cr(VI) adsorption and showed that with the increase in pH of the solution, Cr (VI) removal was decreased. The adsorption isotherm was corresponded to the Langmuir model. The kinetic data was in agreement with the pseudo first order model. The thermodynamic studies showed that Cr (VI) adsorption on the cellulose adsorbent was endothermic and spontaneous. The cellulose adsorbent, Kraft paper, in powder and sheet forms can remove Cr (VI) from water solutions. In the operating conditions of pH 2, powdery adsorbent dose 3 g in 50 mL of CHROMIUM solution with the concentration of 10 mg/L in 25 ° C after 2 h, 99. 16% CHROMIUM (VI) removal yield was obtained.

Introduction: Hexavalent CHROMIUM (VI) is a very strong oxidizing agent that, despite its many uses in various industries, duration of the exposure can lead to lung cancer, deep wounds (in the hands, arm, tongue and palate), nasal septum perforation, burning and inflammation in the nose, lung and upper respiratory tract, asthma, contact dermatitis, damage to the kidneys and liver, and skin allergy. This study aimed to determine the activated carbon efficiency in CHROMIUM adsorption (VI) from air flow and its effective parameters.Material and Method: In this experimental study, CHROMIUM mists were generated by a nebulizer (3A model, Italy). Performance of activated carbon in the Cr (VI) adsorption and its influencing factors such as air flow rate (1 and 3L/min), the initial Cr concentration (0.05, 0.15, 1 and 10 mg/m3) and bed depth (2.5, 5 and 10 cm) were investigated. Yoon-Nelson and Thomas models were used to predict performance of adsorbent column and correlation test was used to determine accordance between the model and actual data.Result: Activated carbon adsorption capacity increased with increasing of bed depth but decreased with increasing of flow rate and inlet concentration. The results showed that the Yoon-Nelson and Thomas models with a correlation coefficient above 0.9953 matched with the experimental data.Conclusion: The results indicated that activated carbon has a high efficiency in Cr (VI) adsorption, so that its efficiency at flow rate of 3 L/m, depth of 5 cm and concentration of 20 TLV and TLV was 85.42 and 71.83 percent respectively.

In order to investigate the influence of vermicompost (VC) on the concentration of nickel (Ni) and CHROMIUM (Cr) in soil and rice this research was conducted as a split plot based on randomized complete block design with three replications in 2008. Main factor (fertilizer) was added to soil in 6 levels, 20 and 40 ton ha-1 VC, 20 and 40 ton ha-1 VC enriched with 50% chemical fertilizer (CF), CF (based on soil testing comprise 100 kg. ha-1 urea, 150 kg. ha-1 triple super phosphate and 100 kg. ha-1 potassium sulphate) and control. Sub plot, were considered application periods that comprise 1, 2 and 3 years application. Results showed that the maximum available Ni (2.20 mg kg-1) belonged to 3 years application of 40 ton enriched VC. In 3 continuous years application of enriched 20 and 40 ton ha-1 measured the highest available Cr (0.109 mg kg-1). The highest concentration of Ni in root belong to 3 continuous years application of 40 ton VC +50% chemical fertilizer that was about 63% more than control treatment. With application of 40 ton VC per hectare during 2 and 3 years, measured the maximum Ni concentration in grain with about 2 times of control treatment. Also, the most content of Cr in root (8.43 mg kg-1) and grain (4.25 mg kg-1) belonged to 3 years application of enriched 40 and 20 ton ha-1, respectively.

To evaluatethe effects of supplementing diets of growing Japanese quails (n=450; 7 days old) with CHROMIUM (Cr) yeast and / or mannan oligosaccharides (MOS) on productive performance, carcass traits and the immune system are reported. Diets were a basal diet (control) or the basal diet supplemented with 600 mg Cr-yeast/kg (Cr 1), 1200 mg Cr-yeast/kg (Cr 2), 1.0 g MOS/kg, Cr 1+MOS or Cr 2+MOS. Quails fed Cr 1, MOS or Cr 1+MOS diets had similar final live body weight and weight gain, with both groups being higher than the control. Feed conversion tended to be improved with dietary supplements. Carcass traits did not differ among treatments. Primary and secondary humoral immune responses of quails fed the supplemented diets were higher than the control. Plasma total proteins and triiodothyronine were increased, while plasma total lipids and cholesterol were decreased by the supplements. In conclusion, dietary supplementation with Cr yeast (600 mg/kg) and / or mannan oligosaccharides (1.0 g) improved productive performance and immunity and reduced total cholesterol of growing Japanese quails.

In this research, the effect of high-frequency resistance welding (HFRW) parameters on microstructure and mechanical properties of seamless 2. 25Cr-1Mo ferritic steel as spiral (helical) finned tube used in industrial boilers was investigated. So HFRW was implemented on actual (Industrial) samples by changing multiple parameters including Current, Electric Potential, Welding Speed (Rotation Speed) and Pitch, then metallography, fusion weld, tensile strength and hardness tests were performed on various sections of the samples according to ASTM and international standard. The results of metallographic and mechanical properties tests indicated that in order to obtain a minimum of 90 percent welding diffusion, depends on optimum welding parameters, fin tip and tube tip position of resistance welding, hydraulic pressure jack setting on squeeze roller and pitch FPI (fin per inch) to dissimilar joints between CHROMIUM-molybdenum low alloy steels tube to CHROMIUM high alloy steels of coil strips. Furthermore as the lower pitch and fin thickness are selected, the higher quality of fin tube welding diffusion is achieved.

Adsorption of CHROMIUM ions (VI) and (III) in aqueous solution was investigated using activated carbon prepared from olive wastes, by one step physical activation with steam. After adsorbent material characterization using adsorption capacity of methylene blue, iodine and phenol, BET surface area, Fourier Transform InfraRed (FT-IR) spectroscopy, pHpzc, surface functions based on the Boehm method and, Scanning Electron Microscopy (SEM), the effect of different parameters (initial pH, absorbent dosage, initial concentration of solutes, time) on the adsorption of CHROMIUM ions were carried out in a batch system. The obtained activated carbon has a large specific surface area of 1050, 9 m2/g and good adsorption capacity for iodine (1017 mg/g) and methylene blue MB (349 mg/g), which confirm that its structure is essentially composed of micropores (61 % of the surface) and mesopores. It has a basic chemical nature. Experimental results showed that the adsorption capacity of the prepared activated carbon was strongly dependent on solution pH. It was found that the initial pH of 2. 0 was most favorable for Cr(VI) adsorption, and basic pH was best for Cr(III) removal. The adsorption process was studied using two kinetic models (pseudo-first order and pseudo-second order) and three functions isotherms (Langmuir, Freundlich, Temkin). The results showed that the adsorption process follows the pseudo-second order kinetics and the adsorption data were found to agree with the Langmuir isotherm model. Maximum adsorption capacity for Cr (VI) was 74, 9 mg/g at pH 2, and 14, 3 mg/g at pH 9 for Cr (III), and was comparable to results reported by other researchers working on activated carbon prepared from various solid wastes. Temperature effect was determined using the thermodynamic parameters. Negative values of Δ H0 and Δ G0 proved the feasibility of the adsorption process with its spontaneous and exothermic natures. Tests of desorption were performed in three different media: neutral (distilled water), acidic (2N hydrochloric and acetic acid solutions) and alkaline (2N NaOH solution). The magnitudes of desorption efficiency in the acetic acid medium were 94% and 71% for Cr(VI) and Cr(III) respectively.

In this work, batch studies were conducted to evaluate the effect of environmental factors on the rate of Cr (VI) reduction from synthetic wastewater of metal plating industry by Bacillus cereus. The effect of different inoculum volumes (5, 10, 15 and 20 mL), pH (5, 7 and 9), temperatures (20, 30 and 40 °C) and initial concentrations of Cr (VI) (10, 50, 100 and 200 mg/L) for the best performance of CHROMIUM removal were investigated during 72 h of cultivation by Bacillus cereus. Complete reduction of Cr (VI) by Bacillus cereus was achieved after 48 h of incubation under optimized conditions of pH 7, inoculum volume of 5 mL, initial CHROMIUM concentration of 50 mg/L, and temperature of 40 oC. The results showed the highest rate of reduction at the lowest Cr (VI) concentration (0.104 mg/L.h). Atomic absorption spectroscopy analyses under optimized conditions showed the concentration of Cr (III) in the culture supernatant was 49 mg/L after 48 h. The presence of almost all the reduced Cr (III) in the supernatant revealed Cr (VI) -reductase in Bacillus cereus is mainly associated with the soluble fraction of the enzyme. High Cr (VI) concentration resistance and high Cr (VI) reducing ability of Bacillus cereus make it a suitable candidate for bioremediation.