The Use of Clay-Polymer Nanocomposites in Wastewater Pretreatment

Some agricultural effluents are unsuitable for discharge into standard sewage-treatment plants: their pretreatment is necessary to avoid clogging of the filtering devices by colloidal matter. The colloidal stability of the effluents is mainly due to mutual repulsive forces that keep charged particles in suspension. Pretreatment processes are based on two separate stages: (a) neutralization of the charges (“coagulation”) and (b) bridging between several small particles to form larger aggregates that sink, leaving clarified effluent (“flocculation”). The consequent destabilization of the colloidal suspension lowers total suspended solids (TSSs), turbidity, and other environmental quality parameters, making the treatments that follow more efficient. Clay-based materials have been widely used for effluent pretreatment and pollutant removal. This study presents the use of nanocomposites, comprised of an anchoring particle and a polymer, as “coagoflocculants” for the efficient and rapid reduction of TSS and turbidity in wastewater with a high organic load. The use of such particles combines the advantages of coagulant and flocculant by neutralizing the charge of the suspended particles while bridging between them and anchoring them to a denser particle (the clay mineral), enhancing their precipitation. Very rapid and efficient pretreatment is achieved in one single treatment step

Direct Relationship Between Electrokinetic Surface-charge Measurement of Effluents and Coagulant Type and Dose

AbstractColloidal stability due to rejection between particles with identical charge is a severe problem in water treatment. Pretreatment of industrial effluents such as olive mill or cowshed dairy wastewater includes the addition of “coagulants” aimed at neutralizing the colloids and reducing their rejection. However, the amount and type of coagulant are usually determined by “trial-and-error” jar tests due to the lack of an efficient method to evaluate the effluents' charge. This study presents a method for direct evaluation of the efficiency of type and dose of coagulants based on particle charge detector (PCD) measurements of the colloidal effluents and the coagulant to be used as the neutralizing compound. This presumably trivial procedure is not common, apparently due to the fact that measuring colloidal charge with a PCD is less widely used than ζ potential measurements. A few examples of the effective use of this procedure are presented

Adsorption of benzyltrimethylammonium to montmorillonite: application to herbicide formulations Adsorption du benzyltriméthylammonium sur la montmorillonite: application à la …

MATERIALS AND METHODS The clay mineral used was Wyoming Na-montmorillonite SWy-1 obtained from the Source Clays Repository (Clay Minerals Society, Columbia, MO). BTMA was purchased from Aldrich (Milwaukee, WI, USA). Analytical grade alachlor (Chem Service, West Chester, PA) was used for making the formulations, whereas a commercial formulation (EC)(Alanex, 480g ai/kg, Agan Chemical Manufactures LTD., Ashdod, Israel) was used as a standard formulation. The electrolytes used were: NaCl, LiCl, NaClO4, Na2SO4, CsCl

Optimization of adsorption of hydrophobic herbicides on montmorillonite preadsorbed by monovalent organic cations: interaction between phenyl rings

This study aimed to optimize organo-clay formulations for reduction of leaching of the herbicides alachlor, metolachlor, and norflurazon, which include a phenyl ring in the structure. The adsorbed amounts of herbicides increased severalfold when montmorillonite was preadsorbed by an organic cation; benzyltrimethylammonium (BTMA) was more effective than benzyltriethylammonium (BTEA). Fourier transform infrared studies indicated interactions between alachlor molecules and adsorbed BTMA. The adsorption affinity of the herbicides increased with BTEA loading up to the cation exchange capacity (CEC) of montmorillonite but reached a maximum at a BTMA loading of 5/8 of the CEC. The enhanced adsorbed amounts of herbicides are mainly due to interactions between the phenyl rings of herbicide molecules and organic cations, which are favored with the smaller cation, BTMA. BTMA preadsorbed on the clay

new tailor made bio organoclays for the remediation of olive mill waste water

A systematic study aimed at obtaining new organoclays for the treatment of Olive Mill Waste water (OMW) has been performed. Several organoclays have been prepared by loading different amounts of the biocompatible surfactant Tween20 onto the K10 montmorillonite (MMT). Complementary kinetic and equilibrium studies on the adsorption of the Tween20 onto the MMT have been carried out and the characterization of the new tailor-made bio-materials has been performed by means of the XRD and FT-IR measurements. Finally the prepared bio-organoclays have been successfully applied for the OMW remediation and they proved to be highly effective in decreasing the organic content (OC) to an extent that depends on both the amount of loaded surfactant and the experimental protocols applied