Plant materials have been found useful in decontamination of water Polluted with phenolic compounds. The detoxification effect is due to peroxidases contained in plant tissue. Enzyme mediated oxidative coupling of phenol is followed by precipitation of the formed polymer and its removal from the aqueous phase. A synthetic wastewater buffered at pH=7.4 containing 0.9 mM phenol was treated in this research with cut Raphanus sativus root and its juice. Cut Raphanus or Raphanus juice were added separately as enzyme source to phenol solution in buffer and in tap water in two series of experiments. The reaction was initiated by the addition of hydrogen peroxide. After three hours stirring the phenol content of the mixtures was determined. More than 90% of phenol was removed in both cases.

A new constructed wetland was built to purify one Polluted river in Taiwan, and this study was conducted to evaluate the treatment efficiency of the wetland. Due to the very limitation of available budget, several water quality items, which were stipulated by Taiwan’s Environmental Protection Administration for rivers, in the influent and effluent of wetland were analyzed and evaluated. These items included water temperature, pH, DO, BOD5, TSS, and NH4 +-N. The results showed that the average removal rates of total (unfiltered) BOD5, TSS and NH4+-N were 36.9 %, 71.8 % and 47.1%, respectively. With the HRT more than 3.4 days, the wetland could treat the Polluted river water effectively. Longer HRT in this wetland appeared no obvious improvement on the removal rate of TSS or NH4+-N. However, BOD removal rate increased while the HRT (Hydraulic Retention Time) increased to about 5 days. In this wetland, the calculated mean first order reaction rate constant (kT) for BOD5 was 0.15/day with a standard deviation of 0.13/ day and for NH4+-N was 0.24/ day with a standard deviation of 0.18/day. It is also concluded that there is a linear proportional relationship between BOD concentrations in the effluent of wetland and its influent mass loading rates, with the coefficient of determination (R2) of 0.6511. Similar result was seen for NH4+-N as well, with the coefficient of determination (R2) of 0.5965. TSS removal rate was found to be linearly proportional to its influent mass loading rate, with the coefficient of determination (R2) of 0.4875.

Introduction: Acetamiprid (AP) is one of the most widely used pesticides in the neonicotinoid class. AP residues in the environment have received considerable due to their potential toxicity to humans. Therefore, it is important to remove AP from the aqueous solution. Materials and Methods: In the current study, response surface methodology (RSM) was used as an efficient approach to optimize the removal of AP using the electro-Fenton (EF) process. The effects of the main variables, including reaction time, AP concentration, current density, and H2O2 dosage were investigated and optimized. ANOVA technique was also used to identify the Fisher’, s value (F-value) and P-value of the model. Results: The predicted AP removal efficiency by the model was in good agreement with the obtained experimental results with correlation regression of 0. 98. The ANOVA test proved that the developed quadratic model was significant with very low P-values less than 0. 05, the high F-value of 240. 1, and regression coefficients close to 1 at a 95% confidence level. The optimum condition for AP removal efficiency of 99. 02% was attained at the reaction time of 12 min, AP concentration of 3. 5 mg L-1, the current density of 12 mA cm-2, and H2O2 dosage of 86 μ, L. Conclusion: RSM was employed as a suitable method to optimize the operating condition and maximize the AP removal. Herein, the EF process as an ecofriendly electrochemical advanced oxidation process (EAOP) successfully applied to remove AP from the water and wastewater.

In this work, copper oxide nano sorbent (CONS) with an average diameter of 30 nm is synthesized by polyvinyl alcohol-based sol-gel method to remove heavy metal ions from an aqueous solution. The produced nanopowder is fully characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). Various physicochemical parameters such as solution pH, nano-sorbent dosage, solution temperature, contact (mixing) time, initial concentration of lead ion, and the initial volume of lead ion sample are investigated and optimized by the "one at a time" method. Based on the experimental data, the optimum conditions for the full removal of lead ions with an initial concentration of 30 ppm, include pH 6, a sorbent dosage of 1.6 mg ml-1, a solution temperature of 25 ºC, and a contact time of 13 min. The experimental results showed that the adsorption of lead ions by copper oxide nanoparticles has a good fit with Langmuir isotherm and follows the pseudo-second-order kinetics model. The experimental data shows the synthesized CuO nanoparticles are an effective sorbent for the removal of Pb(II), Fe(II), and Cu(II) from water with maximum capacities of 33.7, 20.2, and 18.8 mg g-1, respectively.