Hierarchical Zeolites as Catalysts for Biodiesel Production from Waste Frying Oils to Overcome Mass Transfer Limitations.

Hierarchical crystals with short diffusion path, conventional microcrystals and nanocrystals of ZSM-5 zeolites were used for biodiesel production from waste frying oils and were assessed for their catalytic activity in regard to their pore structure and acidic properties. Produced zeolites were characterized using XRD, nitrogen adsorption-desorption, SEM, TEM, X-ray fluorescence, and FTIR. Pore size effect on molecular diffusion limitation was assessed by Thiele modulus calculations and turnover frequencies (TOF) were used to discuss the correlation between acidic character and catalytic performance of the zeolites.

Effect of algal surface area and species interactions in toxicity testing bioassays.

Single and multispecies algal bioassays were assessed using copper toxicity with three green algae (Scenedesmus subspicatus, Scenedesmus quadricauda and Ankistrodesmus angustus) and one blue-green algae species (Oscillatoria prolifera). Single and multispecies toxicity tests were conducted based on cell density as per standard toxicity testing, and on equivalent surface area. A higher copper sulfate toxicity was registered for O.

Synthesis of Binderless ZK-4 Zeolite Microspheres at High Temperature.

Binderless zeolite macrostructures in the form of ZK-4 microspheres were prepared using anion-exchange resin beads as shape-directing macrotemplates. The particles were synthesized under hydrothermal conditions at different temperatures and treatment times. The influence of the different synthesis parameters was investigated by X-ray diffraction, scanning electron microscopy, fluorescence X, nitrogen adsorption measurements and Si solid-state NMR.

Preliminary economic assessment of the use of waste frying oils for biodiesel production in Beirut, Lebanon.

In this study, a method for assessing the costs of biodiesel production from waste frying oils in Beirut, Lebanon, was investigated with the aim of developing an economic evaluation of this alternative. A hundred restaurant and hotel enterprises in Beirut were surveyed for promoting them in participating in the biodiesel supply chain, and for data collection on waste frying oils generation, disposal methods and frequency, and acquisition cost. Also, waste frying oils were collected and converted into biodiesel using a one-step base catalyzed transesterification process.

Evaluation of copper toxicity using site specific algae and water chemistry: Field validation of laboratory bioassays.

Studies of metal toxicity to microalgae have predominantly been conducted using single non-target algae species and without due regard for the chemistry of the treated waters, leading to ineffective or excessive algaecide treatments. In this study, indigenous multi-algal species (Scenedesmus quadricauda, and Scenedesmus subspicatus and Oscillatoria agardhii) were used in laboratory toxicity bioassays under simulated field water chemistry (pH = 7.2, hardness = 196 mg L as CaCO, and alkalinity = 222 mg L as CaCO) to determine the optimum copper sulfate treatment dose to control algae growth in an irrigation canal.