VOLUME 20, NO1, MAR 1998

Adsorption of some aliphatic organic acids from aqueous solutions on activated carbons

Adsorption of a series of lower aliphatic and different unsaturated organic acids from their aqueous solutions on the surface of activated carbons, prepared from indigenous precursors like wood (Acacia arabica), rice husk (low ash) and lignitic coal (Lakhra) have been studied. It has been found that adsorption pattern follows Traube's rule and to a large extent depends upon porosity and chemical nature/surface of the adsorbent. It has further been established that the degree of adsorption of a particular acid depends upon the polarity of carboxylic group, the length of side chain as well as the nature or type of bonding. Freundlich and Langmuir plots were drawn and their constants calculated and elucidated. It has also been inferred that active carbons prepared from cellulosic precursors have proven better towards the acid adsorption as compared to that prepared from lignitic coal.read more

---

TANZIL H USMANI ,A H K YOUSUFZAI ,TAMOOR WAHAB AHMAD ,M TAHIR MOTON ,

A comparison of the thermal oxidation of nickel and cobalt impregnated charcoal

Pure charcoal was impregnated with nickel and cobalt. The effect of metal impregnation on the thermal oxidation of charcoal was studied and compared by employing thermogravimetry and differential thermal analysis. The results show the impregnation of cobalt results in a signifcant decrease in the decomposition temperature of charcoal. The energies of activation for decomposition, calculated from the thermogravimetric curves, are 42.96, 38.61 and 30.58 kJ/mol for pure, nickel and cobalt impregnated charcoal respectively.read more

---

RIAZ QADEER ,RIZWAN HUSSAIN ,

A mathematical model for explanation of ion exchange of the boric acid adsorption

Bed depth service time and legit methodologies are very effective in examining ion exchange process for removing boron by columnar operation. They are exployed in this paper for the development of a convenient mathematical model. Such a model provides opportunity for the assessment in process parameters among which are the bed depth, ion exchange rate, influent concentration as well as the pH effect on the service time. Experimentally obtained data in the laboratory fit Bohart-Adams equation on double logarithmic paper as a result of which a linear regression line emerges. This method helps engineers in designing ion exchange columns by means of similar operations.read more

---

SAMI SAHIN ,

Effect of temperature on the adsorption of Mg2+ on kaolin from aqueous solutions and the stability constants for complex formation

Kaolin, an inexpensive clay mineral, available in abundance in our country has been employed as an adsorbent for the removal of Mg2+ from water at pH 7.0 within the temperature range (303-328 K). The linearity of the plots indicated langmuir type isotherms. The reaction was exothermic. At 303 K the H-rel(+)/Mg2+ ads ratio n was fractional. At 318 K at a time only one H+ was released per metal ion adsorption and at 328 K two H+ were released to the aqueous phase. Strong chemical bondings took place between oxygen atom of the surface and Mg2+ resulting in a surface complex species. In spite of the difference in structure between TiO2 and kaolin, they show a similarity in their interaction with magnesium. Temperature had a significant effect on H-rel(+), and the stability constants also increased with increasing temperature.read more

---

FARID ULLAH KHAN ,M A QASIAR ,SHAKILA BEGUM ,

Coordination compounds of anthraquinone dioxime (AQD) with cobalt(II), nickel(II) and copper(II)

The present research deals with the synthesis and structural studies of anthraquinone dioxime complexes having general formula [M(L)(2)] where L stands for anthraquinone dioxime and M for Cu(II), Co(II), and Ni(II). All compounds were characterized by elemental and metal ion analysis and various spectroscopic techniques such as ultraviolet/visible, NMR and infrared spectra. Disappearance of peak around 3000-3400 cm(-1) in the I.R spectra was considered to be a diagnostic test for the formation of complexes. The Uv-visible spectra show the D-4h symmetry of the complexes according to the expectation. This structure is further supported by conductance and magnetic data.read more

---

MASOOD AHMAD ,SAEED UR REHMAN ,MOHAMMAD ARSHAD ,

Transition metal complexes of phenhomazine derivative dibenzo[b,f][1,5]diazocine-6 : 12-dione with copper(II), cadmium(II), mercury(II) and zinc(II)

The eight membered cyclic diamine are versatile chelating agents and often exhibit the ability to confer various geometries on their complexes. The complexes of dibenzo[b,f] [1:5]diazocine-6:12-dione (commonly called dianthranilide) are reported with that of salts of copper, zinc, cadmium and mercury. The titled compound can be viewed as modified form of DACO and PHZ, in which the vibrational freedom of carbon (C-6 and C-12) is further restricted by fusing with oxygen. The structure of the complexes is assigned on the analysis of their spectral, magnetic and conductance data. The molecular weight of the ligand is confirmed by its electron impact mass spectrum.read more

---

MASOOD AHMAD ,SAEED UR REHMAN ,

Chelates of acetylsalicylic acid with group IB and IIB metals - Spectroscopic and X-ray diffraction studies

The chelation of acetylsalicylic acid with group IB and IIB metals is reported. The metal contents in different synthesised compounds were ascertained using atomic absorption technique. Their analytical data, infrared spectra and x-ray diffractographs have also been employed in their characterization.read more

---

C M ASHRAF ,M ZAFAR IQBAL ,BUSHRA KHAN ,

An investigation of inorganic contaminants of potable water of Karachi

Drinking water available at Karachi was collected from 11 stations and was analysed for a number of pollutants. The concentration of most of the impurities lie within the permissible: criteria of drinking water quality. The results suggest that most of the inorganic pollutants were introduced through the distribution system since the concentrations were relatively low at Kinjhar lake, a major source of water supply.read more

---

ZAHIDA BEGUM ,SAEEDAN BEGUM ,S A MALIK ,A SAJID BARI ,

Chemical investigation of the effluents of selected industries of NWFP, Pakistan

150 samples of effluents were collected from the drain mouths and at different distances from the waste water drain for physico-chemical properties and heavy metals like Pb, Ag, Cu, Zn, Fe, Ca, Cr, Cd, Mn and Ni, using spectroscopic techniques. The results of our investigation are presented and discussed.read more

---

SARAWAR KHAN ,HAIDER SHAH ,JAMIL SHAMROZ ,M RASUL JAN ,

Monitoring of industrial effluents

Effluents collected from industries of different localities of NWFP were investigated for various parameters such as DO, BOD, total alkalinity, total hardness, chlorides, nitrites, sulphites and various cations, physical parameters like temperature pH, conductivity, TDS, DS and SS were also investigated in the same effluents. The values were compared with the standard, general variation in some of the parameters were observed. The implications of these parameters were also discussed.read more

---

MIRAJ MUHAMMAD ,YOUSAF IQBAL ,SULTAN ALAM ,