Funthenalized chitosan (CS) was composited with mesoprous SBA-15 and characterized via. different techniques such as FT-IR and FE-SEM. Subsequently, this new material was applied for simulations ultrasound-assisted adsorption of Pb ion and alizarin red S (ARS) dye after their complexation. Efficient conventional variables in adsorption process such as initial ARS and Pb concentration, adsorbent mass and sonication time were studied by small central composite design (CCD) and optimized with desirability function approach. Lack of fit testes and model summary statistics for linear, 2FI, quadratic and cubic models were investigated and according to the insignificant lack of fit and maximizing the R-squared (R), adjusted R-squared and the predicted R-squared quadratic model was selected for other step analysis for removal of ARS dye, while, for Pb ions 2FI model was selected as best model. Quadratic model ANOVA for ARS dye removal shows the F-value parameter (683.91), very low p-value model (<0.0001) and p-value lack of fit (0.0568) that implied this model was highly significant. Also, 2FI model ANOVA for Pb ions removal shows the F-value parameter (282.51), very low p-value model (<0.0001) and p-value lack of fit (2.05). According to desirability function approach maximum removal percentage of ARS (87.61%) and Pb ions (83.54%) was shown at optimum of condition that were set as at: 25 and 25mgL, 0.028g and 11.8min for initial ARS and Pb ions concentration, adsorbent mass and sonication time, respectively. Finally, it was found that the equilibrium and kinetic of adsorption process follow the Langmuir isotherm and pseudo-second-order kinetic model, respectively. From the Langmuir isotherm, maximum monolayer capacity (q) was obtained 50.25 and 57.14mgg for ARS and Pb ions removal, respectively.

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In this work, we focused on development of a new techniques by coupling of ultrasound irradiation, cloud point method and magnetite solid phase microextraction for the extraction and preconcentration of Cr(III) ions from aqueous solutions. In order to reduce cost and improve practicability of proposed process a new efficient and regenerable magnetite sorbent (functionalized chitosan grafted-amino graphene oxide (GO) decorated by zinc ferrite nanoparticles (CS-GO-Zn: FeO)) was synthesized through hydrothermal method and then characterized by FT-IR, FE-SEM, EDS and XRD analysis. Effect of initial sample volume and type, volume and concentration of eluent on the ER% were investigated and optimized using one at a time method. Correlation between the main and interaction effects of other operational parameters such as Cr(III) ion concentration, CS-GO-Zn: FeO mass, sonication time, pH and solution temperature on the ER% were investigated and optimized by central composite design coupled with desirability function approach. The results revealed that there were significant effects for most investigated terms on the ER% and maximum ER% of 88.09% was obtained in desirability value of 1.0. This maximum efficiency was obtained at 0.035µg/mL Cr(III) ion concentration, 40.16°C temperature, 0.016g of CS-GO-Zn: FeO, pH 6.36 and 9.20min sonication time. In addition, under the optimal conditions the linear range, limit of detection, enrichment factor and relative standard deviation were found to be 0.02-4.4µg/mL, 0.002µg/mL, 23.23 and 1.68% respectively. Finally, the method was successfully applied to the separation and preconcentration of Cr(III) ion from tap, river and mineral waters.

Simultaneous preconcentration and determination of auramine o (AO) and crystal violet (CV) dyes from aqueous solution was conducted by ultrasound assisted (dispersive) solid phase microextraction (UASPME) based on SnO2/SnS composite loaded activated carbon (SnO2/SnS‐NCs‐AC). The prepared of SnO2/SnS‐NCs‐AC was characterized by FESEM and XRD analysis. Main and interaction influences of operational parameters such as pH, sonication time, amounts of sorbent, and type of eluent on extraction efficiency were investigated by central composite design and optimized with desirability function approach (DFA). ANOVA was conducted and shows that optimized values were found at 15.33 min sonication time, 0.019 g SnO2/SnS‐NCs‐AC mass, pH 5.46 and among different solvents, dimethyl formamide was selected as an efficient eluent. Under this conditions recoverees percentage were obtained 82.85% and 86.70% for AO and CV, respectively. Based on F‐test under ANOVA all main effect and interaction effect of understudy parameters has the significant effect on the responses. At optimum conditions, limit of detection (0.0015 and 0.001 mg/l), limit of quantitation (0.4 and 0.4 mg/l), limit of linearity (9.0 and 9.0 mg/l), enrichment factor (33.48 and 83.71) and percent relative standard deviation (3.44 and 4.20) were found to be for auramine o and crystal violet dyes, respectively. Finally, the method was successfully applied for the preconcentration and determination of AO and CV in water samples and ER% of 89.0‐97.0 and 96.2–98.0% as acceptable range were found to be for AO and CV samples, respectively.