Effective coupling of phenol adsorption and photodegradation at the surface of micro-and mesoporous TiO2-activated carbon materials

International audienceNovel titania supported activated carbon catalysts were prepared by a straightforward titania coating route of a microporous activated carbon (AC) derived from shea nut shells, and investigated in phenol photocatalytic degradation. The proposed coating method enables a fixation of the preformed titania anatase nanoparticles (TiO2 NPs) in the external porosity thus allowing their accessibility towards UV irradiation, without causing any reduction of the AC specific area. Interestingly, the coating treatment reshapes the porous texture of the as-prepared TiO2–AC composite materials resulting in an improvement of the adsorption capacity and the formation of an additional mesoporosity on the TiO2-AC surface. Photocatalytic experiments carried out in a batch reactor led to 97% elimination rate of phenol in an aqueous solution with the AC catalysts containing TiO2 NPs in the range from 11 to 34 wt%. The photodegradation performance of the TiO2–AC catalysts was maintained over several successive cycles, without the need of any regeneration treatment. Considering both the textural and microstructural features of the composite materials and their associated phenol removal kinetics, in this paper, we provide new insights into phenol photodegradation pathway involving an effective coupling of adsorption and photodegradation functionalities, resulting in a photo-assisted regeneration mechanism of the catalyst

Manipulation of Agricultural Habitats to Improve Conservation Biological Control in South America

International audienceStable and diversified agroecosystems provide farmers with important ecosystem services, which are unfortunately being lost at an alarming rate under the current conventional agriculture framework. Nevertheless, this concern can be tackled by using ecological intensification as an alternative strategy to recuperate ecosystem services (e.g., biological control of pests). To this end, the manipulation of agricultural habitats to enhance natural enemy conservation has been widely explored and reported in Western Europe and North America, whereas in other parts of the world, the investigation of such topic is lagging behind (e.g., South America). In this forum, we gathered published and unpublished information on the different ecological habitat management strategies that have been implemented in South America and their effects on pest control. Additionally, we identify the various challenges and analyze the outlook for the science of conservation biological control in South America. More specifically, we reviewed how different agricultural practices and habitat manipulation in South America have influenced pest management through natural enemy conservation. The main habitat manipulations reported include plant diversification (intercropping, insectary plants, agroforestry), conservation and management of non-crop vegetation, and application of artificial foods. Overall, we noticed that there is a significant discrepancy in the amount of research on conservation biological control among South American countries, and we found that, although intercropping, polycultures, and crop rotation have been reported in agroecosystems since pre-Inca times, more systematic studies are required to evaluate the true effects of habitat management to implement conservation biological control for pest control in South America