Ammonium Cerium Sulfate Research Articles

Protection Effect of Ammonia on CeNbTi NH3-SCR Catalyst from SO2 Poisoning

CeNbTi catalyst was poisoned in different sulfur poisoning atmospheres at 300 °C for 6 h and then was evaluated for selective catalytic reduction (SCR) of NOx with NH3. The catalyst deactivation upon SO2 exposure was effectively inhibited in the presence of NH3. Temperature-programmed decomposition (TPD) analyses were applied to identify deposit species on the poisoned catalysts by comparison with several groups of reference samples. Diffuses reflectance infrared Fourier transform spectroscopy (DRIFTS) over CeNbTi catalysts with different poisoning pretreatments and gas purging sequences were designed to investigate the roles of NH3 in the removal of surface sulfites and sulfates. More ammonium sulfates including ammonium bisulfate and ammonium cerium sulfate were generated instead of inert cerium sulfate in these conditions. The mechanisms about the formation and transformation of surface deposits upon sulfur poisoning w/wo NH3 were explored, which provided a basis for developing Ce-based mixed oxides as SCR catalysts for stationary sources.

Grafting of O-Carboxymethyl Chitosan with Acrylonitrile and Studying some of its Properties and Applications

Preparation of o-carboxymethyl Chitosan was done, wich is important derivative of chitosan. Grafting copolymerization of acrylonitrile onto o-carboxymethyl chitosan was accomplished using ammonium cerium sulfate (CAS) as an initiator. Resulting graft of o-carboxymethyl chitosan was characterized by FT-IR spectrum and DTA analysis to be compared with o-carboxymethyl chitosan. Properties such as water swelling and solubility were studied for each, whereas,. Percentage of grafting efficiency (GE%) and yield of grafting (GY%) were determined. The efficiency of grafted ocarboxymethyl chitosan (CMCh-g-PAN) to remove dyes(direct black dyes, dispersed red dyes) from industrial waste water was also determined. The results reveal good efficient absorption of black dyes more than red dyes. Efficiency from different concentrations of grafted o-carboxymethyl chitosan(CMCh-g-PAN) to reveal percentages of elimination ions from their solutions metallic ions Cu2+,Pb2+,Cd2+and Sn2+ from their solutions at room temperature with mechanical stirring for 24 hrs were also determined .It has been shown that grafted o-carboxymethyl chitosan has important role in elimination of lead ion comparing with other ions, As a result, elimination percentages of ions increase as follow: Cd2+< Sn2+< Cu2+<. Pb2+

Highly sensitive spectrofluorimetric procedure for the assay of phenothiazine derivatives in the presence of their sulfoxide oxidized product.

A validated straightforward and sensitive spectrofluorimetric procedure was developed to assay trifluoperazine hydrochloride, promethazine hydrochloride, and perazine maleate. The procedure was dependent on oxidation of the investigated phenothiazines using a known excess of ammonium cerium sulfate as oxidizing agent and overseeing the fluorescence intensity of the resultant Ce3+ ion as the product of this reaction at λcx = 254 nm. and λem = 355 nm. Various parameters controlling the reaction were investigated and optimized. Linear calibration graphs were found in the general concentration range 5-30 ng/ml with a general correlation coefficient range 0.9994-0.9995. Limits of detection were 0.97, 0.70 and 0.56 ng/ml, whereas limits of quantification were 3.24, 2.12 and 1.89 ng/ml for trifluoperazine hydrochloride, promethazine hydrochloride and perazine maleate, respectively. The procedure was implemented successfully for analyses of the cited drugs in their trade dosage preparations such as tablets and syrups. The effect of possible interference from common excipients and their sulfoxide oxidized product was studied and the procedure showed good recovery of the drugs under study in their available dosage preparations. The possible effect of structure variation of the studied drugs on the experimental conditions and sensitivity observed with each one was also discussed.