Iranian Journal of

Backgrounds and Objective: Surfactants are one of the largest pollutants which exist in urban and industrial wastewaters. Large quantities of surfactants have entered to the environment since last decade due to increased use of synthetic detergent in industrial and home consumptions.In this study, the efficiency of UV/H2O2 process in removal of linear alkylbenzane sulfonate (LAS) from aqueous solutions was investigated.
Materials and Methods: In this study methylene blue active substane(MBAS)method and spectrometery were used to determine anion and residual surfactant respectively. In this study important variables were H2O2 concentration, initial concentration of surfactant, pH and duration of UV radiation. The effect of UV/H2O2 process on the degradation of LAS was analyzed statistically by using Multiple Linear Regression test.
Results: The resulted showed that after 20 minute, ultraviolet radiation solely removed 38.44 percent of Anionic detergent, Hydrogen peroxide showed no significant removal of detergent solution in the time course study. The efficiency of UV/H2O2 process in 10, 20 and 30 minute were to 86.2, 90 and 96.5 %, respectively.
Conclusion: The results showed that the efficiency of ultraviolet radiation and hydrogen peroxide process in anionic detergent was not significant thoogh it was considerable in combination process (UV/H2O2).

Background and Objectives: Soil pollution by oil compounds is a serious environmental and ground water problem throughout the world. Total petroleum hydrocarbons (TPH) are a combination of many distinctive compounds. Some of these compounds in exposure with human and animal can cause cancer, disorder central nervous system, liver and lungs affects. The objective of this research was to investigate gasoline removal (C10 – C 28) using Brij 35 and Tween 80 from polluted soil. Materials and Methods: In this experimental study, the efficiency of soil washing with nonionic surfactants (Brij 35, Tween 80) for remediation of gasoline polluted soils was studied. The effects of soil washing time, agitation, surfactant concentration, and pH on the removal efficiency were studied. Results: The results showed that gasoline removal efficiency increased with increasing agitation speed and washing time. In addition, it was found that removal efficiency of gasoline was decreased by increasing surfactant concentration. But, increasing pH did not have remarkable effect on removal efficiency of gasoline. The efficiencies of Tween 80 and Brij 35 for removal of gasoline under optimal condition were 70 -80 and 60- 65% respectively. Conclusion: The results showed that soil washing with non ionic surfactants was effective in removal of gasoline from polluted soil and it can be recommended for treating surface soil polluted.

Background and Objectives: Rapid growing of Triton X-100 application in industries results in its appearance in effluents  and threaten the aqueous ecosystems. Triton X-100 is not biodegradable and can accumulate in food chain.

Materials and Methods: In this study, sorption capacity of six synthesized zeolites with different regular porous structure was studied for triton X-100 (TX-100) surfactant and the results were compared with Clinoptilolite natural zeolite of Damavand region.

Results: Within all zeolite studied, Beta(200) showed the highest sorption capacity (about 575 mg/g), which is due to its regular pore structure with large pore diameter, channel intersections, high SiO₂/Al₂O₃ ratio and high surface area. Langmuir monolayer isotherm and pseudo-second-order kinetic equation could provide well-fitted to the experimental data in simulating adsorption behavior of TX-100 over Beta(200) zeolite.

Conclusion: The adsorption feature was internal sorption and the intraparticle diffusion might be a rate-limiting control for Beta(200) zeolite. Results of experiments demonstrated that the hydrophobic zeolites with large pore diameter such as Beta(200) could be effective sorbents for industrial wastewater treatment features.

Background and Objective: Surfactants can be found in soaps, detergents, pharmaceutical products, personal care products, as well as in leather industries. In this study, adsorption of Sodium Dodecyl Sulfate (SDS) on magnetic multi-walled carbon nanotubes in the aqueous solutions was investigated.

Materials and methods: Surfactant concentration, adsorbent dosage, and pH values were considered as variables. Residual surfactant was measured using methylene blue method and adsorbent characteristic was determined by X-Ray diffraction and Fourier transform infrared spectroscopic analysis. Adsorption capacity, adsorption isotherm, and kinetic reaction were also investigated.

Results: Adsorption investigations demonstrated that the increase in initial SDS concentration or pH values, led to the decrease in SDS adsorption. Conversely, the same result was achieved by decreasing adsorbent dosage. After 120 min SDS adsorption became stable. By increasing in SDS concentration from 15 to 150 mg/L, adsorption capacity improved from 8 to 61 mg/g. Isotherm and kinetic data demonstrated that experimental data pursued Langmuir isotherm (R²=0.993) and pseudo-second order equation (R²=0.992).

Conclusion: Magnetic multiwall carbon nanotubes can be used as an effective and useful sorbent for SDS removal due to several advantages including: high adsorption capacity, relatively low equilibrium time, and easy separation of magnetic multiwall carbon nanotubes from aqueous solutions.

Background and Objective: Main sources of 4-chlorophenol wastewater are petroleum industry, coal, paper and resin production. The aim of this study was to compare the performance of raw and cationic surfactant modified nanoclay in removal of 4-chlorophenol from aqueous solutions.
Materials and Methods: The influence of contact time, initial pH of solution, adsorbent dosage and 4-chlorophenol concentration as effective parameters in adsorption process and the influence of modification solution pH and surfactant loading rates were investigated. The modified nanoclay was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy. Finally, the isotherm and adsorption kinetics were investigated.
Results: The removal efficiency of 4-chlorophenol was increased by increasing the initial pH from 3 to 11, so that after of 120 min, the absorption efficiency at an initial 4-chlorophenol concentration of 100 mg/L and 0.25 g adsorbate was 26 and 95.5 % at pH 3 and 11, respectively. Under the same conditions the removal efficiency for the raw nanoclay was 2 and 9% at pH 3 and 11, respectively. The FTIR and XRD analyses revealed that the nanoclay structural changed from hydrophilic to hydrophobic and the interlayer spacing was increased. The adsorption of 4-chlorophenol on raw and modified nanoclay was consistent with Langmuir and pseudo-second-order kinetics. The maximum absorption capacity of raw and modified nanoclay was 0.5 and 25.77 mg/g, respectively
Conclusion: The modification of nanoclay with cationic surfactant increased the adsorption efficiency of 4-chlorophenol.