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FeCeOx has been successfully synthesized by ultrasonic impregnation method and applied in diclofenac removal in heterogeneous Fenton process. The effects of ultrasonic density, impregnation time, mole ratio of Fe and Ce and calcination temperature were investigated. Nitrogen adsorption/desorption, SEM, XRD, HRTEM, Raman and XPS analyses were characterized. Stability and reusability of FeCeOx were evaluated. The results indicated that 83% degradation efficiency of diclofenac was achieved by FeCeOx under the optimum preparation conditions. Fe ions were distributed uniformly in crystal structure and the solid solution structure of FeCeOx with a lattice constriction was formed. Exposed crystalline plane (200) with a relatively high surface energy may be the main reason to provide high catalytic activity of FeCeOx. Oxygen vacancies took part in catalytic process and a portion of them were oxidized after reaction. FeCeOx showed an excellent chemical stability and reusability in heterogeneous Fenton process.

Dynamic effects of health and inter-state and inter-industry knowledge spillovers, Total Factor Productivity (TFP) growth and convergence in US agriculture are examined using recently developed procedures for panel data and a growth accounting model. Strong evidence is found to support the hypothesis that TFP converges to a steady state. Health care supply in rural areas and research spillovers from other states and from nonagricultural sectors are found to have significant impacts on the productivity growth rate in both the short and the long run. These results suggest a richer set of opportunities for policy makers to enhance productivity growth than previously considered.

The hypothesis of induced innovation is tested for U.S. agriculture using a high-quality state-level panel data set and three disparate testing techniques—time series, direct econometric, and nonparametric. We find little support for the hypothesis. That conclusion is robust across testing techniques. However, as with all empirical tests of this hypothesis conducted to date, ours focus only on the demand side of the hypothesis. The hypothesis could have been rejected simply because the marginal cost of developing and implementing input-saving technologies for the relatively expensive inputs is greater than for the relatively cheap inputs. Copyright 2009, Oxford University Press.

In this study, a new type of sludge-derived biochar material with high tetracycline removal efficiency, named magnetic Fe3O4 biochar, was accomplished by KOH activated and loaded with magnetic Fe3O4. The particles with spherical pellets observed by SEM, as well as the XRD patterns, indicated that magnetic Fe3O4 nanoparticles were successfully loaded onto the biochar. We studied the adsorption effects and mechanisms of the following three different adsorption materials for tetracycline: biochar (BC), magnetic Fe3O4, and magnetic biochar (MBC), and the loading conditions and reusability of the materials were also considered. The adsorption effects were as follows: Fe3O4 (94.3%) > MBC (88.3%) > BC (65.7%), and the ratio of biochar to ferric salt was 0.2:1; the removal effect reached the best result. Under an acidic condition, the adsorption capacity of all the materials reached the maximum, and the adsorption of tetracycline in water, by three adsorbents, involves chemical adsorption as the leading process and physical adsorption as the auxiliary process. Various characterizations indicated the removal of tetracycline, including pore filling, electrostatic interaction, hydrogen bond action, and cationic-π action. Complex bridging is a unique adsorption mechanism of magnetic Fe3O4 and magnetic biochar. In addition, the magnetic biochar also possesses π–π bond interaction. The magnetic materials can still maintain a certain amount of adsorption capacity on tetracycline after five cycles. This study proved that the magnetic sludge-based biochar are ideal adsorbents for the removal of tetracycline from water, as well as an effective route for the reclamation of waste sludge.

This paper studies the sonocatalytic degradation of diclofenac in water using FeCeO-catalyzed ultrasound. The effects of pre-adsorption and gas addition were investigated. Nitrogen adsorption/desorption, SEM, XRD, Raman and XPS analyses of FeCeO before and after sonication were characterized. The proposed mechanism was based on the microstructure changes of FeCeO and reactive-species-scavenging performances. The results show that FeCeO has excellent performance in catalyzing an ultrasonic system in water, and 80% of diclofenac was removed in 30min ([Diclofenac]=20mg/L, FeCeO amount=0.5g/L, pH=6, ultrasonic density=3.0W/cm, ultrasonic frequency=20kHz, temperature=298K). The Fe, Ce, and O elements remained highly dispersed in the structure of FeCeO, and the solid solution structure of FeCeO remained stable after the reaction. Ce (III) was gradually oxidized to Ce (IV) and Fe (III) was gradually reduced to Fe (II) after the reaction, which indicates that Fe and Ce ions with different valences coexisted in dynamic equilibrium. The amount of oxygen vacancies in FeCeO significantly decreased after the reaction, which indicates that oxygen vacancy participated in the ultrasonic process. Singlet oxygen O was the primary reactive species in the degradation process, and the hydroxyl radicals OH and superoxide radical anion O also participated in the reaction. FeCeO had excellent chemical stability with negligible leaching ions in the ultrasonic process.

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A system of ultrasound radiation coupled with Zn was applied to degrade diclofenac. The effects of initial pH, dosage of Zn and ultrasound density were investigated. To further explore the mechanism of the microcosmic reaction, the fresh and used Zn powders were characterized by SEM, XRD and XPS. Radical scavengers were used to determine the oxidation performance of strong oxidizing free radicals on diclofenac, including hydroxyl radicals and superoxide radicals. The results showed that the optimum removal of diclofenac reached to over 85% at pH of 2.0 in 15min, with Zn dosage of 0.1g/L and ultrasound density of 0.6W/cm. TOC removal of 72.6% in 15min and dechlorination efficiency of diclofenac reached 70% in 30min. Characterization results showed that a ZnO membrane was generated on the surface of Zn particles after use. According to the mass spectrometry results, several possible pathways of diclofenac degradation were proposed, and most diclofenac was turned into micro-molecules or CO finally. The synergistic effect of US/Zn in the reactions led to a proposed degradation mechanism in which zinc could directly attack the target contaminant diclofenac because of its good reducibility with the auxiliary functions of ultrasonic irradiation, mechanical shearing and free radical oxidation.