Ecological toxicity of reactive X\|3B red dye and cadmium in both their single form and their combined form on wheat was studied using the experimental method of seed and root exposure. The single factor exposure ind...Ecological toxicity of reactive X\|3B red dye and cadmium in both their single form and their combined form on wheat was studied using the experimental method of seed and root exposure. The single factor exposure indicated that the inhibitory rate of wheat root elongation was significantly increased with the increase in the concentration of the dye in the cultural solution, although seed germination of wheat was not sensitive to the dye. The toxicity of cadmium was greatly higher than that of the dye, but low concentration cadmium (<40 mg/L) could promote the germination of wheat seed. Interactive effects of the dye and cadmium on wheat were complicated. There was no significant correlation between the inhibitory rate of seed germination and the concentrations of the dye and cadmium. Low concentration cadmium could strengthen the toxicity of the dye acting on root elongation. On the contrary, high concentration cadmium could weaken the toxicity of the dye acting on root elongation.展开更多
Dyes often include toxic, carcinogenic compounds and are harmful to humans＇ health. Therefore, removal of dyes from textile industw wastewater is essential. The present study aimed to evaluate the efficiency of the c...Dyes often include toxic, carcinogenic compounds and are harmful to humans＇ health. Therefore, removal of dyes from textile industw wastewater is essential. The present study aimed to evaluate the efficiency of the combination of zero valent iron （ZVI） powder and multi-walled carbon nanotubes （MWCNTs） in the removal of Reactive Red 198 （RR198） dye from aqueous solution. This applied research was performed in a batch system in the laboratory scale. This study investigated the effect of various factors influencing dye removal, including contact time, pH, adsorbent dose, iron powder dose, initial dye concentration, and temperature. The equilibrium adsorption data were analyzed using three common adsorption models： Langmuir, Freundlich and Temkin. Besides, kinetic and thermodynamic parameters were used to establish the adsorption mechanism. The results showed, in pH = 3, contact time = 100 min, ZVI dose = 5000 mg· L- 1, and MWCNTs dose = 600 mg· L- 1 in 100 mg· L- 1 dye concentration, the adsorption efficiency increased to 99.16%. Also, adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data fitted well with the Freundlich isotherm （R2 = 0.99）. The negative values of AGo and the positive value of △H0 （91.76） indicate that the RR198 adsorption process is spontaneous and endothermic. According to the results, the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.展开更多
文摘Ecological toxicity of reactive X\|3B red dye and cadmium in both their single form and their combined form on wheat was studied using the experimental method of seed and root exposure. The single factor exposure indicated that the inhibitory rate of wheat root elongation was significantly increased with the increase in the concentration of the dye in the cultural solution, although seed germination of wheat was not sensitive to the dye. The toxicity of cadmium was greatly higher than that of the dye, but low concentration cadmium (<40 mg/L) could promote the germination of wheat seed. Interactive effects of the dye and cadmium on wheat were complicated. There was no significant correlation between the inhibitory rate of seed germination and the concentrations of the dye and cadmium. Low concentration cadmium could strengthen the toxicity of the dye acting on root elongation. On the contrary, high concentration cadmium could weaken the toxicity of the dye acting on root elongation.
文摘Dyes often include toxic, carcinogenic compounds and are harmful to humans＇ health. Therefore, removal of dyes from textile industw wastewater is essential. The present study aimed to evaluate the efficiency of the combination of zero valent iron （ZVI） powder and multi-walled carbon nanotubes （MWCNTs） in the removal of Reactive Red 198 （RR198） dye from aqueous solution. This applied research was performed in a batch system in the laboratory scale. This study investigated the effect of various factors influencing dye removal, including contact time, pH, adsorbent dose, iron powder dose, initial dye concentration, and temperature. The equilibrium adsorption data were analyzed using three common adsorption models： Langmuir, Freundlich and Temkin. Besides, kinetic and thermodynamic parameters were used to establish the adsorption mechanism. The results showed, in pH = 3, contact time = 100 min, ZVI dose = 5000 mg· L- 1, and MWCNTs dose = 600 mg· L- 1 in 100 mg· L- 1 dye concentration, the adsorption efficiency increased to 99.16%. Also, adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data fitted well with the Freundlich isotherm （R2 = 0.99）. The negative values of AGo and the positive value of △H0 （91.76） indicate that the RR198 adsorption process is spontaneous and endothermic. According to the results, the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.
