Insoluble rust waste from the scraping of rusted iron-containing materials represents a cheap, eco-friendly, and available source of iron. LaFeO 3 perovskite-type powders were successfully prepared by solution combustion synthesis using rust waste from an electricity transmission tower manufacturer. Solution combustion synthesis enabled introduction of this insoluble iron precursor directly into the final product, bypassing complex extraction procedures. Catalytic activity in the propylene oxidation of the waste-derived LaFeO 3 with stoichiometric Fe/La ratio was almost identical to the commercial iron nitrate-derived LaFeO 3 , thus demonstrating the viability of this recycling solution. The amount of waste iron precursor was varied and its effect on the powder properties was investigated. A lesser stoichiometric amount of precursor produced a LaFeO 3 –La 2 O 3 binary system, whereas a higher stoichiometric amount led to a LaFeO 3 –Fe 2 O 3 binary system. Catalytic activity of iron-rich compositions in the propylene oxidation was only slightly lower than the stoichiometric one, whereas iron-poor compositions were much less active. This eco-friendly methodology can be easily extended to other iron perovskites with different chemical compositions and to other iron-containing compounds.

The oxaloyl carboxymethyl cellulose (OCMC) complexes of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) metal ions have been synthesized and the coordination of OCMC in these complexes has been investigated through IR spectra, reflectance spectra, and thermal analysis. On the basis of spectral and thermal data an octahedral geometry was assigned to[Mn(II)OCMC(H2O)2]nand[Co(II)OCMC(H2O)2]n, square planar geometry was assigned to[Cu(II)OCMC]n, and tetrahedral geometry was assigned to[Ni(II)OCMC]nand[Zn(II)OCMC]nMetallic Gel complexes.

A rapid amperometric method for the determination of vanadium (V) has been described which involves titration of vanadium (V) as sodium orthovanadate against copper sulphate solution at Ede = − 0.20 V (vs S.C.E.). The accuracy and reproducability of the method is excellent particularly at higher temperature i.e. at 60°C. The method permits the determination of vanadium (V) down to 0.2 mM with an accuracy 1.0%).

The inorganic polymers containing transition metals such as Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized by using succinoyl carboxymethyl cellulose (SCMC) in aqueous media. The newly synthesized polymers were characterized by elemental analysis, IR spectroscopy, TG analysis, UV reflectance spectra and magnetic moment. On the basis of these studies, the composition of the polymeric unit was found to be [M(II)L]n, [Mʼ(II)L.2H2O]n, {[Mˮ(II)L.2H2O]n H2O}, where M= Zn(II), Mʼ = Mn(II), Ni(II) and Cu(II) and Mˮ = Co(II), L = SCMC ligand. On the basis of instrumental techniques, it has been found that the [Zn(II)(SCMC)]n inorganic polymer has tetrahedral geometry, whereas {[Cu(II)(SCMC)].2H2O}n has square planar geometry and [Mn(II)(SCMC).2H2O]n, {[Co(II)(SCMC).2H2O)].H2O}n and [Ni(II) (SCMC).2H2O]n have octahedral geometry. The decomposition temperatures of the inorganic polymers have been determined by TGA. The TGA reveal that the Mn(II) polymer of SCMC is highly thermally stable than rest of the polymers and these polymers can be used as thermal resisting materials.

Todate, available literature, furnishes no informa tion regarding the application of electrometric methods, to study the nature and compositions of the compound formed by the interaction of uranyl nitrate and various tungstate isopolyanions. Much earlier L e f o r t x, ob tained uranyl compounds of the compositions U02 -W04 and U02W04 • 2 W035 H20 etc. by analytical means. His results, however, could not be confirmed by later workers.There is a great difficulty in assigning a definite composition to such a metallic tungstate precipitated by analytical methods, because of the presence of con stitutionally bounded water molecules and hydration of the products, as well as the possibility of formation of double compounds, coprecipatation and occlusion. Analytical results alone fail, therefore, to give a true picture of the polysalt thus formed.Owing to lade of any specific and sensitive electrometric method, the present work was initiated with a view to study the reaction equilibria between uranyl nitrate U02 (N03) 2 and various isopolytungstate by amperometric, pH and conductometric methods of titra tions. The results are being incorporated in the present paper in-continuation of our earlier similar investiga tions 2' 3. Experimental AnalaR (B.D.H.) U02 (N03) 2 -6H20, Na2W04 -2H20, NaC104 and gelatine were used. Air free conductivity water was used for preparation and subsequent dilu tions of the solutions.A manual polarograph with a scalamp galvanometer, was used for entire polarographic and amperometric work. Polarographic behaviour of 1 mm U022® was studied in 0.1 m NaC104 as supporting electrolyte and 0.001% gelatine as maxima supressor. A dropping mer cury electrode with characteristics m2,3tlj6 = 2.52 mg2/s sec~1/2 was used in conjunction with a saturaded calo mel electrode connected through a salt bridge. A reduc tion potential of -1.00 V (vs S.C.E.) was applied for all amperometric titrations, which is beyond the limiting current plateau of the second step of the wave. The first step limiting current plateau was also tried but was found to be unsuitable. The procedure adopted in entire amperometric work is the same as described in our earlier communications 3' 4.The various alkalituungstate solutions were prepared by addition of requisite amounts of A.R. HC1 to standard normal Na2W04 solution at 100 °C. A series of ampero metric titrations were performed using 0.1 m NaC104 as Supporting electrolyte and 0.001% gelatine as a maxima suppressor. pH titrations were carried out with the help of a Cambridge null deflection type pH meter using a glass electrode of 0 -1 2 range and con ductance were recorded by a Tesla Conductivity Bridge.3 C. M. G u p t a , Bull. chem. Soc. Japan 33, 837 [1966]. 4 M. P. J o s h i and C. M. G u p t a , Ind.