in this paper, the sorption activity of Salvadora Persica fine particles provided from internal natural resources in Iran with respect to Crystal Violet, Basic Violet-16 and Basic Blue-41 dyes is investigated. Salvadora Persica particles were modified and prepared via particle size reduction and they were characterized by CHNS, XRD, SEM and FT-IR analysis. In the batch system, the influence of pH, adsorbent dosages and dye initial concentration was investigated. The results of isotherm and kinetics studies show that the Langmuir isotherm and pseudo-second order kinetic have better correlation with the experimental data. Calculations of thermodynamic parameters show negative Gibbs free energy (Δ G) values or spontaneous reaction, the enthalpy (Δ H) changes shows the exothermic process and values of entropy (Δ S) indicate low randomness at the solid/solution interface during the uptake of dyes. So, these locally available cheap adsorbents for the removal of basic dyes from the aqueous solution have high efficiency and can also be utilized for other water pollutants such as toxic elements. Prog. Color Colorants Coat. 10 (2017), 115-128© Institute for Color Science and Technology.

In the present work, we have investigated the sorption efficiency of the treated activated carbon from walnut shell (ACW) towards Direct Red 81 (DR81) and Direct Blue 71 (DB71) for the removal from aqueous solution. The sorption study of ACW at the solid-liquid interface was investigated using kinetic, sorption isotherms, pH effect and amount of adsorbent. Experimental data were analyzed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherms. Langmuir isotherm model (R2=0.9664 and R2=0.9484) fitted the equilibrium data the best other isotherms for DR81 and DB71. According to the results maximum adsorption occurred in acidic pH.The results showed that the sorption processes of DR81 and DB71 on ACW are in good agreement with pseudosecond order kinetic. Maximum amount of adsorbent for adsorption of mentioned dyes was 1 gr.

The use of chitosan as an adsorbent for the removal of oil from oil-in-water emulsion has been investigated in this study. Chitosan is a promising material with various applications in adsorption and is effective in removing several types of pollutants, including vegetable oil. As oil pollution continues to cause significant harm to the environment, adsorption has emerged as a viable method for remediation, and this study seeks to explore its potential in removing oil from wastewater. A series of adsorption experiments were conducted on artificially made oil-in-water emulsions, using chitosan flakes as the adsorbent and cooking vegetable oil as the adsorbate. The study investigated various parameters affecting the sorption capacity, including pH, contact time, oil concentration, adsorbent dose, agitation speed, and temperature. Untreated and unmodified chitosan flakes were used as adsorbents, and the results showed that oil removal efficiencies of up to 80-90% could be achieved by varying individual parameters. Significantly, the peak values were observed individually at 50°C, 30 min of contact time, 0.005 g of adsorbent per 100 mL of emulsion, 0.8% of initial oil concentration, 150 RPM of agitation speed, and a solution pH of 6.02. The potential for improving oil removal with modified chitosan was also discussed, along with an analysis of parameter interaction. The findings suggest that chitosan has significant potential as an adsorbent for oil removal from wastewater and that further research into modifications and optimization of parameters could lead to even greater efficiency in oil removal. Overall, this study contributes to the growing body of research on environmentally friendly and sustainable methods for the bioremediation of oil pollution.

In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employed for adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIR techniques. The Pb(II) adsorption capacity enhanced by 1. 8 times from 60 mg/g (natural zeolite) to 100 mg/g (modified zeolite) at optimal conditions. Factors such as time, pH, temperature, adsorbent dosage and initial concentration were investigated to optimize the adsorption condition. A fast sorption was observed in the initial contact time and equilibrium was achieved in less than 120 min. The optimum pH for lead removal was between 3 and 6. The adsorption capacity was increased and reached the maximum of 90 % at 2 g/L adsorbent dosage. Also, the adsorption increased as the concentration increased up to 500 mg/L and the sorption became constant at higher concentration. It was found that the double-exponential model describes the lead sorption kinetics and the Langmuir– model describe the isotherms.

Background: There are great resources of natural zeolite in Iran. Zeolite, an inorganic ion-exchanger, may be used as a suitable technical-economical solution for water treatment in many regions of Iran. In this study, the characterization of natural zeolite natrolite and the feasibility of removing hardness, cations, and anions were investigated.Methods: First, zeolite composition and type were determined using X-ray Fluorescence (XRF), thermal analysis, and infrared spectrometer. Also, cation exchange capacity (CEC) and its impact on water hardness reduction evaluated. Then, isotherm curves for Fe, Cr, Al, Bi, Cd, Mn, Ca, Mg, Ag, Ni, Zn, Cu, Pb, and their disposition to zeolite phase besides removal rate of the mentioned cations in analyzed water samples identified. Eventually, zeolite structure was rectified using surfactant (HMNDA) for anions removal.Results: Natrolite zeolite was more effective for waters with higher hardness, but it turned out to be moderate for waters with lower hardness. The ability of natrolite zeolite for permanent hardness removal was more than others and was less for temporary hardness. Also, the natrolite zeolite was more effective in removing non-heavy metal cations and by increasing the HMNDA concentration, arsenate anion removed fast from water samples. However, by pH increases in the water sample, the arsenate anion removal arbitrarily changed: less in pH=3. But the removal efficiency got better in alkaline pH. It is obvious that by increasing the pH of water samples, the removal efficiency will decrease. In spite of that, the removal efficiency of chromate ion, in acidity pH, was more than alkaline. The maximum removal of Cr (VI) occurred in acidic media at pH<1.5.Conclusion: The natrolite zeolite could remove different heavy metals from drinking water. Moreover, the removal efficiency of natrolite zeolite was enhansed by surfactant modification.

In this work, the optimization of the synthesis of PAN/Ag nanofiber composites via electrospinning was investigated via Taguchi's experimental design approach. The adsorption capacity of sulfur compounds from natural gas condensate was considered an objective function. The PAN/Ag nanofiber with 11 wt% PAN, 45 wt% AgNO3, 15 kV applied voltage, and 15 cm for a distance of a needle to a collector showed the highest adsorption capacity. The SEM, EDX, TEM, XRD, and FT-IR techniques were employed to elucidate the optimized PAN/Ag nanofiber structure. The results showed the successful synthesis of PAN/Ag nanofibers with diameters in 100-300 nm range and well distribution of Ag nanoparticles in the polymeric matrix. In addition, optimization of the adsorption capacity of PAN/Ag nanofiber in desulfurization of natural gas condensate in batch mode was performed via central composite design. Four factors including adsorbent weight, sulfur concentration in the natural gas condensate, the volume of the sample, and the adsorption time were considered effective factors each in three levels. The ANOVA analysis showed the more important factor in adsorbent performance is the concentration of sulfur in gas condensate and the weight of the adsorbent. The interaction terms between time and concentration and between volume and concentration are also important in response. Moreover, the response surface analysis of interaction terms showed the adsorptive nature of desulfurization.

Grape juice is one of the valuable food and medicinal products obtained from the natural extract of grapes. This substance is rich in nutrients, serves as a source of natural energy, and possesses various medicinal properties. The turbidity of grape juice depends on the presence of suspended particles, polysaccharides, and other suspended substances. To improve the quality of the juice and reduce its turbidity, natural absorbents are employed. In the current research, lemon peel, as a natural adsorbent, was used to reduce turbidity. After various preliminary tests, 40 ml of grape juice with a Brix value of 10 and an initial absorption rate of 2.874 a.u. was obtained using 2 grams of lemon peel. The surface adsorption process was carried out for 4 hours using the response surface method within a temperature range of 20 to 60 °C and a stirring speed of 200 to 600 rpm. Following optimization, the results indicated that a temperature of 35 °C and a stirring speed of 380 rpm were the most effective conditions for turbidity removal, achieving a maximum removal percentage of approximately 58%. The Brix values showed an insignificant difference of only 9% between the final and initial Brix values. Additionally, the DLS analysis evaluating the average particle size yielded values of 5000 nm and 3000 nm before and after the surface adsorption process, respectively, with a dispersion index of 1 and 0.846.

Fluoride is a constituent of natural water. Generally groundwater has been considered as a safe and protected source of drinking water in the rural and developing cities, and little consideration was given to the risks of chemical pollution, particularly to the presence of elevated levels of fluoride, arsenic and nitrate in groundwater. In this study, absorption method of continuous state is used for defluoridation with the bauxite as an absorbent and the graph of equilibrium concentration divided by initial concentration is plotted against the time. This graph helps us to find out the break through the time during the operation of continuous absorption and then optimal data is obtained. Absorption data correlated with Langmuir and Freundlich models but the data fits better to Langmuir’s.

Background: Phenol is an organic pollutant found in industrial effluents that is very toxic to humans and the environment. This study used pomegranate peel ash as a natural absorbent to remove phenol from aqueous solutions.Methods: In this study, pomegranate peel ash in different doses was used as a new adsorbent for the removal of phenol. The effects of contact time, pH, adsorbent dose and initial phenol concentration were recorded. Then, the adsorption data was described with Langmuir and Freundlich adsorption isotherms; Excel software was used for data analysis.Results: The highest percentage of phenol adsorption was observed at pH=7. The optimum amount of adsorbent was 0.6 g/l, and after 120 minutes, the process reached an equilibrium state. The adsorption of phenol decreased following an increase in the pH of the solution. It was also observed that contact time significantly affected the rate of phenol adsorption. The experimental data fit much better in the Freundlich (R2=0.9056) model than in the Langmuir (R2=0.8674) model.Conclusion: Pomegranate peel ash has the potential to be utilized for the cost-effective removal of phenol from aqueous solutions.

Wastewaters produced from various industries and their entry into surface water is one of the most important environmental problems that have harmful effects on aquatic life. Discharging phosphate from urban and industrial wastewater to the aquatic environment causes a lot of algae growth. The aim of this study was to evaluate the removal of phosphate from aqueous solutions using sepia endoskeleton (cuttlebone) powder as a natural biomass, cheap and non-toxic absorbent. This study was conducted in a batch system. Sepia endoskeleton was washed with distilled water. It was then dried at 80 ° C and thoroughly powdered by milling. Physical and chemical properties of the adsorbent were determined using the Particle Sizer, atomic force microscopy, and infrared spectroscopy and X-ray fluorescence. The effects of variables affecting phosphate uptake, such as pH, adsorbent amount, contact time, initial concentration of phosphate and stirring rate were optimized. Also, the isotherm models (Langmuir, Freundlich, Tamkin and Dubbin-Radshkvich) and first-order and second-order kinetics models were used to evaluate the data. The results showed that the highest removal percentage was observed at pH 5, adsorbent content of 5 g/L and contact time of 10 min at initial phosphate concentration of 10 mg/L. Using sepia powder under optimal laboratory conditions, the phosphate ion with the concentration of 10 mg/L was removed with a yield of over 99%. The results indicated that the Freundlich isotherm model gives a better description than other models showing the adsorption of phosphate ions occurs in a heterogeneous surface. Using Langmuir model, the maximum absorption capacity for phosphate was 68. 02 mg/g. The kinetic model of phosphate removal followed the pseudo-second-order model. Besides, the percentage of removal of the real samples was over 98%, indicating the great ability of this natural and inexpensive absorbent to remove this pollutant from the water solutions.