Natural Zeolite Clinoptilolite Application in Wastewater Treatment: Methylene Blue, Zinc and Cadmium Abatement Tests and Kinetic Studies.

In recent decades, several abatement techniques have been proposed for organic dyes and metal cations. In this scenario, adsorption is the most known and studied. Clinoptilolite was considered, since it is a zeolite with a relatively low cost (200-600 $ tons) compared to the most well-known adsorbent used in wastewater treatment.

Simultaneous CO reduction and NADH regeneration using formate and glycerol dehydrogenase enzymes co-immobilized on modified natural zeolite.

In this work, the co-immobilization of formate dehydrogenase (FDH) and glycerol dehydrogenase (GlyDH) enzymes is proposed to reduce CO into formic acid, an important chemical intermediate. The reduction of carbon dioxide is carried out by FDH to obtain formic acid, simultaneously, the GlyDH regenerated the nicotinamide cofactor in the reduced form (NADH) by the oxidation of glycerol into dihydroxyacetone. Natural zeolite was selected as immobilization support given its good properties and low cost.

Synthesis and characterization of ordered mesoporous silicas for the immobilization of formate dehydrogenase (FDH).

This work studied the influence of the pore size and morphology of the mesoporous silica as support for formate dehydrogenase (FDH), the first enzyme of a multi-enzymatic cascade system to produce methanol, which catalyzes the reduction of carbon dioxide to formic acid. Specifically, a set of mesoporous silicas was modified with glyoxyl groups to immobilize covalently the FDH obtained from Candida boidinii. Three types of mesoporous silicas with different textural properties were synthesized and used as supports: i) SBA-15 (D = 4 nm); ii) MCF with 0.

Zn and Cd removal from wastewater using clinoptilolite as adsorbent.

Many industries discharge wastewater from processing into surface and underground waterways, and then, these waste waters must therefore be treated in order to remove heavy metals. The most common treatment used is the activated carbon adsorption, a particularly competitive and effective process; however, the use of activated carbon is not suitable due to the high costs. Then, in order to minimize processing cost, recent investigations have been focused on the use of low-cost adsorbents as zeolites.

Photocatalytic Abatement of Volatile Organic Compounds by TiO Nanoparticles Doped with Either Phosphorous or Zirconium.

The aim of this work is to study the activity of novel TiO-based photocatalysts doped with either phosphorus or zirconium under a UV-Vis source. A set of mesoporous catalysts was prepared by the direct synthesis: TiO_A and TiO_B (titanium oxide synthesized by two different procedures), P-TiO and Zr-TiO (binary oxides with either nonmetal or metal into the TiO framework). Complementary characterizations (N physisorption at 77 K, X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analysis, X-ray Photoelectron Spectroscopy (XPS), and (DR)UV-Vis spectroscopy) were used to investigate the physicochemical properties of the prepared catalysts.