Removing pharmaceuticals and endocrine‐disrupting compounds from wastewater by photocatalysis

Widespread concerns continue to be raised about the increasing presence of emerging contaminants in the environment. Such compounds include a wide range of persistent organic chemicals, including pharmaceuticals and endocrine‐disrupting compounds whose effects are poorly known, often because they have only begun to enter the environment and are showing up in wastewater treatment plants. The occurrence and behavior of these compounds in wastewater are key issues with regard to water reclamation and reuse. Treatment plants are now faced with the challenge of removing the compounds from their effluent before they enter natural waterways. In this regard, photocatalysis is a promising technology for wastewater treatment that offers many advantages over conventional and some advanced treatment options. The application of photocatalysis for the removal of pharmaceuticals and endocrine‐disrupting compounds for wastewater is comprehensively surveyed in this paper. This treatment technology is not intended to replace conventional systems but to supplement for higher‐quality effluent. The assessment places emphasis on the process fundamentals, advantages, and disadvantages of the technology. It also focuses on the current limitations and future research needs. Copyright © 2007 Society of Chemical Industry     

Modeling of photooxidation of acetamide herbicides in natural waters by UV radiation and the combinations UV/H2O2 and UV/O3

The photooxidation of several herbicides belonging to the acetamides group (specifically propachlor, metolachlor and butachlor) by means of a monochromatic UV irradiation in ultrapure water was studied. In the case of propachlor, the quantum yield for its photolysis was evaluated directly, and a value 0.127 ± 0.01 mol Eins^?1 was obtained independent of the pH. The quantum yields for the photolysis of metolachlor and butachlor were determined by using a competition kinetic model which used propachlor as reference compound, and values of 0.56 ± 0.05 and 0.78 ± 0.04 mol Eins^?1 were deduced respectively for metolachlor and butachlor. In a second step, the elimination of the selected herbicides in some natural and mineral waters was studied by means of several oxidation systems: UV radiation alone, and UV radiation combined with hydrogen peroxide and ozone. The influence of the operating variables in these processes (acetamide type, presence or absence of tert‐butyl alcohol and types of waters) are discussed as a consequence of the amounts of herbicides removed. Two different kinetic studies were carried out for the oxidation of the herbicides: the first one for UV radiation alone and UV radiation combined with H₂O₂; the second one for the combination UV radiation plus ozone. In these studies, the specific rate constants were evaluated in every process. Finally, kinetic models for the prediction of the elimination of these herbicides in the natural waters selected by the different oxidation systems are proposed. The values of concentrations predicted by these models agree well with the experimental results obtained. Copyright © 2004 Society of Chemical Industry     

Translation of MAT Kinetic Data to Model Industrial Catalytic Cracking Units

Bench‐ and laboratory‐scale reactors are required to infer kinetic data for catalytic cracking units. One of the most common methods is the microactivity test (MAT, ASTM D‐3902–92), that emulates the catalyst‐to‐oil ratio using a fixed‐bed reactor and a semibatch accumulator of liquids. Translation of data obtained from MAT tests in order to infer kinetic parameters to model continuous industrial units is, consequently, difficult and uncertain. In this work, the extraction of kinetic data obtained in a MAT reactor is analyzed. Estimation of a kinetic rate equation to evaluate instantaneous conversion in MAT reactors is performed. The activation energy obtained is kinetic and can be used during the modeling of riser reactors. It was possible, also, to infer values of the remaining catalytic activity after each experiment; these values were used to adjust a hyperbolic deactivation function, useful to model industrial riser reactors.     

Application of natural hydroxyapatite in the treatment of polluted water: Utilization of dromedary bone as bioadsorbent

In this study, the dromedary bone waste was valorized by the obtainment of hydroxyapatite (HAp) and its application to remove crystal violet (CV) dye from aqueous solution. Fourier transform infrared spectroscopy, X-ray diffraction, elemental analysis X-ray fluorescence spectrometer (XRF), particle size laser analysis, and the point of zero charge pH value (pHpzc) were realized to characterize the natural adsorbent. The capacity of HAp to adsorb CV was measured at different contact times, pH values, and initial dye concentrations. The results showed that the model that better described the experimental data of adsorption kinetics was the pseudo-second-order kinetic model (PSO). Freundlich model well fitted the sorption isotherms. A maximum sorption capacity of 266.66 mg/g of CV dye on natural HAp was obtained. Hence, dromedary bone treated might be valorized as a natural adsorbent for water treatment with low environmental risks.     

Acid‐Controlled Chemodivergent Synthesis of Three Differently Substituted Quinolines via Site Selective Coupling of ortho‐ Aminoaryl Ketones with α‐Enolic Dithioesters

A straightforward approach for the chemodivergent synthesis of quinolines is described through site‐selective coupling of ortho‐aminoaryl ketones with α‐enolic dithioesters (DTEs) under solvent‐free conditions. The operationally and user‐simple one‐pot methodology is based on the trifunctional nature of DTEs. Both the carbonyl and the thiocarbonyl moiety in α‐enolic dithioesters were employed for the efficient construction of three differently substituted quinolines in a chemoselective manner simply by variation of an easy to handle acid catalyst.

     

Melt‐spun polylactic acid fibers: Effect of cellulose nanowhiskers on processing and properties

Bio‐based continuous fibers were processed from polylactic acid (PLA) and cellulose nanowhiskers (CNWs) by melt spinning. Melt compounding of master batches of PLA with 10 wt % CNWs and pure PLA was carried out using a twin‐screw extruder in which compounded pellets containing 1 and 3 wt % of CNWs were generated for subsequent melt spinning. The microscopy studies showed that the fiber diameters were in the range of 90‐95 µm, and an increased surface roughness and aggregations in the fibers containing CNWs could be detected. The addition of the CNWs restricted the drawability of the fibers to a factor of 2 and did not affect the fiber stiffness or strength, but resulted in a significantly lower strain and slightly increased crystallinity. Furthermore, CNWs increased the thermal stability, creep resistance and reduction in thermal shrinkage of PLA fibers, possibly indicating a restriction of the polymer chain mobility due to the nanoscale additives. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Process automation in the pharmaceutical industry—a case study of process automation at the caps holdings drug factory

This brief exercise reviews a process automation project at the CAPS Holding pharmaceutical plant in Harare.

CAPS is a holding company producing and distributing industrial and medical drugs in Zimbabwe. It is 54% government owned. At the top of the company is the Managing Director of CAPS Holdings. The CAPS drugs production wing is headed by a General Manager who supervises a number of divisional managers. The plant is located in the medical drugs division and is directly controlled by the medical drugs production manager. The person directly in charge of the plant is the penicillin plant manager. The maintenance of the plant is done by the workshops division.

The CAPS Holdings project involved the switch in 1983 from a manual penicillin vial filling and packaging process to an automatic one.     

Exploring policy options for a transition to sustainable heating system diffusion using an agent-based simulation

Change in home heating to more efficient and renewable systems is important for a sound climate policy. The present paper aims to identify potential interventions for the uptake of wood-pellet heating in Norway using an agent-based model (ABM). The theoretically based, empirically founded, agent-based simulation demonstrates that financial support, i.e., a stable wood-pellet price, and technical development, i.e., functional reliability improvement, have to be established all at the same time for a successful wood-pellet market to start. Furthermore, a soft intervention through persuading households to use environmentally beneficial heating system is not a promising driver for wood-pellet diffusion. Limitations and suggestions for future work are also discussed.     

Exploiting social partners in robot learning

Social learning in robotics has largely focused on imitation learning. Here we take a broader view and are interested in the multifaceted ways that a social partner can influence the learning process. We implement four social learning mechanisms on a robot: stimulus enhancement, emulation, mimicking, and imitation, and illustrate the computational benefits of each. In particular, we illustrate that some strategies are about directing the attention of the learner to objects and others are about actions. Taken together these strategies form a rich repertoire allowing social learners to use a social partner to greatly impact their learning process. We demonstrate these results in simulation and with physical robot ‘playmates’.