Davoud Balarak; Edris Bazrafshan; Yousef Mahdavi
Abstract
Background & objective: Chromium, found in many industrial effluents, is one of most important heavy metal with health and environmental risks. Therefore, the aim of this study is to survey the effect of Cr (VI) removal by using Cyperus rotundus Weed biomass. Material & methods: This empirical ...
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Background & objective: Chromium, found in many industrial effluents, is one of most important heavy metal with health and environmental risks. Therefore, the aim of this study is to survey the effect of Cr (VI) removal by using Cyperus rotundus Weed biomass. Material & methods: This empirical study was done in lab scale. The variation of pH, dose of adsorbent, contact time, and concentration of chromium were investigated. The adsorption data was explained by adsorption isotherms and kenitics.The residual concentration was analyzed by spectrophotometer in maximum wavelength of 540 nm. Results: It was determined that the pH value of 3, contact time of 60 min, adsorbent dosage of 4 g/L and Cr (VI) concentration of 10 mg/L were the optimum conditions for adsorbents. The most Cr (VI) removal efficiency of 99% was obtained for Cystoseira indica biomass in optimum conditions. The equilibrium data is best fitted on Langmuir isotherm and the adsorption kinetic model follows pseudo-second model. The maximum capacity of adsorption was 10.12 mg/g. conclusion: The results revealed that by using Bio-absorption the removal of Cr+6 can be done quickly and effectively.
Hosein Alidadi; Hassan Karimian; Edris Bazrafshan; Ali Asghar Najafpoor; Shahrbanoo Rafe
Abstract
Background and Objective: Textile industry is one of the largest consumers of dyes. Approximately 75% of global dye production is used for dyeing textile, leather, and paper products. Dyes due to their complexstructure are mostly stable, toxic, carcinogenic, mutagenic, and resistant to biodegradation; ...
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Background and Objective: Textile industry is one of the largest consumers of dyes. Approximately 75% of global dye production is used for dyeing textile, leather, and paper products. Dyes due to their complexstructure are mostly stable, toxic, carcinogenic, mutagenic, and resistant to biodegradation; they also can cause allergies and skin conditions in humans.This study aimed to evaluate the efficacies of multi‐walled carbon nanotubes and palm ash for dye removal from textile wastewater in Baluch region ofIranshahr in Iran. Methods: This experimental study was performed on textile wastewater with a dye concentration of 20 mg/L in 2013. The efficacy of multi‐walled carbon nanotubes and palm ash for dye removal at different concentrations, durations (30, 60, 90, 120, and 150 minutes), and pH ranges (3, 5.7, 9, and11) was investigated. Dye concentration in different samples was measured, using a spectrophotometer at a wavelength of 525 nm. Results: The rates of dye removal using multi‐walled carbon nanotubes at pHs of 3, 5, 7, 9, and 11, dye concentration of 20 mg/L, and adsorbent concentration of 0.05 g/L were 85.5%, 93.4%, 88.4%, 81.3%, and 75.3%, respectively during 180 minutes. The corresponding values for palm ash were 88%, 92.8%, 96%, 92.2%, and 88.7%, respectively. The rates of dye absorption were 1710, 1868, 1769, 1626, and 1506 mg/g for multi‐walled carbon nanotubes and 1763, 1857, 1921, 1844, and 1775 mg/g for palm ash, respectively. According to Langmuir isotherm model, adsorption isotherms were R2=0.876 and R2=0.980 for carbon nanotubes and palm ash, respectively. The maximum removal of chemical oxygen demand (COD) inmulti‐walled carbon nanotubes was obtained at pH=5, adsorbent concentration of 0.05, and contact time of 180 min (73.4%). For palm ash, maximum removal was achieved at pH=7, adsorbent concentration of 0.05,and contact time of 180 min (70.6%). Conclusion: Dye removal from textile wastewater can be promoted by increasing reaction time. Dye and COD removal by multi‐walled carbon nanotubes and palm ash was desirable. In fact, in multi‐walled carbonnanotubes, efficacy was desirable at acidic pHs, while in palm ash, neutral pH was considered desirable. Therefore, use of palm ash for the removal of environmental pollutants can be cost‐effective, given its high abundance. Paper Type: Research Article