Yosef Pour Eshgh; Ayyob Rastegar; Ahmad Allahabadi; Zahra Rezaee Gazal abad; Abdolmajid Gholizadeh
Volume 20, Issue 1 , March and April 2013, , Pages 72-83
Abstract
Background: The effluent of textile industries is high dyefully and this is one of most problems for environmental health engineers. Two Azo dyes biosorption, direct black 19 and direct red 23, on Cystoseira indica, an invasive macroalga in Iran, has been investigated using visible absorption spectroscopy. ...
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Background: The effluent of textile industries is high dyefully and this is one of most problems for environmental health engineers. Two Azo dyes biosorption, direct black 19 and direct red 23, on Cystoseira indica, an invasive macroalga in Iran, has been investigated using visible absorption spectroscopy.
Materials and methods: Pre-treatment and chemical cross-linking with CaCl2, have been conducted in order to improve the stability as well as the biosorption capacity of the algal biomass. All measurements were conducted by UV-Visible Spectrophotometer. The effects of operating parameters such as contact time, pH, initial dye concentration and amount of biosorbent on the dye removal efficiency were investigated. The biosorption has been described in terms of isotherm and kinetic models; from the maximum adsorption capacity values, an estimation of the algal specific surface area was made.
Results: It has been found that biosorption kinetics can be described according to the pseudo second order model and biosorption equilibrated for 120 min (89.3% of direct red 23 and 69.02% of direct black 19 removed). Maximum biosorption found at pH 5 (2.4mg/g). It also observed increasing initial dye concentration and decreasing biomass dosage would reduce dye removal. Isotherm studies also revealed the dye biosorption on algal biomass followed from Freundlich model. Conclusion: Biosorption of selected Azo dyes onto algal biomass, Cystoseira indica was fast and more dye is eliminated in the first hour. So, by determining the optimum conditions of contact time, pH, initial dye concentration and biosorbent dosage, Cystoseira indica can be used as an inexpensive sorbent for removal of Azo dyes from aqueous solutions.
Roshanak Rezaei Kalantary; Ahmad Allah-Abadi; Mehdi Farzadkia; Ayyob Rastgar; Ahmad Joneidi Jafari; Abdolmajid Gholizadeh
Volume 19, Issue 3 , September and October 2012, , Pages 277-286
Abstract
Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients ...
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Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients (sodium, potassium, and sulfate) from silt-loamy soils. Materials and Methods: In this empirical, applied study, three polyethylene columns (height 50 cm, inner diameter 10 cm), filled with sandy clay loam soil, were randomly selected. Then, 10 kg of compost per square meter were sprayed onto the columns, and leachates exiting the columns were routinely analyzed for pH, electrical conductivity, sulfate, sodium, potassium, lead, chromium, and cadmium. Data analysis was performed with Excel and SPSS software using Kruskall-Wallis test. Results: The data showed that the use of enriched and unenriched compost leachate decreased pH (from 7.43±17.0 to 6.7±0.25 and 7.07±0.11, respectively) and increased the electrical conductivity (EC) (from 1.8±0.3 mSiemens/m to 3.7±0.12 and 12.87±0.41 mSiemens/m respectively). Leakage of metals in the unenriched treatments was not significantly different from the control (p>0.78), but leakage with three metal-enriched compost applications was significant compared with control (p