Open Access Original Research Article

Assessment of Levels of Heavy Metals in Paints from Interior Walls and Indoor Dust from Residential Houses in Nairobi City County, Kenya

J. K. Ogilo, A. O. Onditi, A. M. Salim, A. O. Yusuf

Chemical Science International Journal, Page 1-7
DOI: 10.9734/CSJI/2017/37392

Aim: This study assessed the levels of Pb, Cr, Cd and Zn in settled indoor dust and paint chips.

Study Design: Samples were obtained from twelve selected residential houses within Nairobi County, Kenya.

Place and Duration of Study: GoK Laboratories, Department of Chemistry, JKUAT between February 2016 and November 2016.

Methodology: A modified version of EPA method SW846 3050B was used to digest the samples, and Flame Atomic Absorption Spectrophotometer (Shimadzu AAS-6200) used to analyze samples for the metals. Pearson correlation coefficient was determined for the various metal pairs in paint chips as well as in the dust samples. Also, it was calculated for the given metals in the dust and paint chips samples from a particular sampling point.

Results: The mean concentration of the metals in both the dust and paint chip samples were in the order Zn>Pb>Cr>Cd. The mean concentrations of Zn, Pb, Cr and Cd  were 366.14 µg/g, 129.12 µg/g, 82.65 µg/g, and 27.40 µg/g for the dust samples and 321.77 µg/g, 289.59 µg/g, 77.54 µg/g, and 73.45 µg/g for the paint chip samples respectively. Pb, Cd, and Zn in the paint chips showed a negative relationship while Cr had a positive correlation.

Conclusion: The metals in the paint chips were found to be of common origin while the correlation of the various metal pairs in the dust suggested more diverse sources. Paint from interior walls is not the only contributor of heavy metals in the settled indoor dust.

Open Access Original Research Article

Characterization and Utilization of Citric Acid Modified Cow Hoof for Adsorption of Cadmium and Copper from Wastewater

I. Osasona, A. O. Adebayo, A. E. Okoronkwo

Chemical Science International Journal, Page 1-15
DOI: 10.9734/CSJI/2017/32537

Aims: To investigate the ability of citric acid modified cow hoof (CCH) to remove Cd (II) and Cu (II)) from simulated wastewater.

Place and Duration of Study: Chemistry Laboratory of Afe Babalola University, Ado – Ekiti, Nigeria.

Methodology: The characterization of the citric acid modified cow hoof was carried out through FTIR, SEM and EDX analyses. Batch studies were also conducted to investigate the effect of operation parameters on the adsorption of the metals. Kinetic parameters were analysed using the non-linear forms of pseudo-first order, pseudo-second order and Elovich kinetic models. Non-linear regression analysis of the equilibrium data were carried out using Langmuir, Freundlich, Redich-Peterson, Dubinin Raduskevich and sips models.

Results: The results obtained showed that, the adsorption of the two metals was pH, solute concentration, time and temperature dependent. The kinetic modelling followed pseudo-second-order kinetic model for both metals while the equilibrium adsorption data were best described by Redlich-Peterson and Sips isotherm models for Cd (II) and Cu (II) respectively. Thermodynamic parameters obtained showed that the adsorption of both metals was spontaneous and endothermic in nature.

Conclusion: Removal of cadmium and copper ions from simulated wastewater using citric acid modified cow hooves (a low-cost adsorbent) is feasible.

Open Access Original Research Article

Effects of Different pH Values on Dissolution and Recovery of Zinc and Manganese from Spent Zinc– Carbon Batteries Using Ascorbic Acids

O. E. Bankole, E. A. Samson, S. A. Adebisi, A. D. Folawewo, S. K. Ogunbowale

Chemical Science International Journal, Page 1-9
DOI: 10.9734/CSJI/2017/36624

The improper disposal of solid batteries containing manganese and zinc has adverse effects from both an environmental and economic standpoint. It would therefore be useful to be able to recover the compounds of zinc and manganese in these batteries so that these materials might either be re-used or properly disposed of.

This research presents the results of the effects of different pH values on the dissolution of zinc and manganese from waste zinc – carbon batteries using mixtures of ascorbic acid and sulfuric acids. The waste batteries were manually separated into various components, and the inner cathode and anode electrodes were ground into powder. This was followed by the extraction of 10 g of battery paste with a mixture of 15 g/dm3 ascorbic acid, 0.5 M or 1.0 M H2SO4 at different pH values from 2 to 12 (at about 80°C) and an agitation speed of about 20 rpm. The resulting solutions analyzed using atomic absorption spectrophotometry (AAS) showed that the concentration of Mn extracted from the battery was higher than that of Zn at pH’s of 2, 4, 6. The concentrations ranged from 1200 – 10000 mg/kg and 200 – 4200 mg/kg for Mn and Zn, respectively. This indicates that more Mn than Zn would be extracted at lower pH than at higher pH values. The extraction of both metals into the solution decreased with increased in pH of the solution mixture and these results are shown to be consistent with a kinetic model. It was also observed that the recovery of metals from the battery was pH dependent and that more was recovered using NaOH rather than KOH solutions.

Open Access Original Research Article

Spectrophotometric Method for the Determination of Carbendazim in Orange Juice Samples Marketed in Senegal

El Hadji Tombé Bodian, Ibrahima Sarr, Souleymane Sambou, Alphonse Mendy, Coumba Gueye, Cheikh Diop, Ibrahima Diagne, Diène Diégane Thiaré, Pape Abdoulaye Diaw, Mame Diabou Gaye-Seye, Atanasse Coly

Chemical Science International Journal, Page 1-7
DOI: 10.9734/CSJI/2017/37770

A spectrophotometric method for the quantitative analysis of carbendazim in orange juice is described here. The analytical method was developed for the determination of fungicide in acetonitrile and 10-2 M NaOH aqueous solution, with large linear dynamic range (LDR), low limit of detection (LOD) and limit of quantification (LOQ) values of 0.07-0.7 ng/mL and 0.2-2.3 ng/mL, respectively, and small relative standard deviation (RSD) values less than 2%, according to the medium. This spectrophotometric method was applied to the evaluation of carbendazime residues in spiked orange juice, with satisfactory mean recovery values within (80-120%).

Open Access Original Research Article

Effect of Cooking on Arsenic Reduction in Two Rainfed Rice Varieties of Bangladesh and Their Health Risk Assessment

Makoto Sekine, Masahiro Tokumura, Mohammad Raknuzzaman, Md Habibullah Al Mamun, Md Kawser Ahmed, Muhammad Rafiqul Islam, Yuichi Miyake, Takashi Amagai, Shigeki Masunaga

Chemical Science International Journal, Page 1-7
DOI: 10.9734/CSJI/2017/37982

To investigate the effects of cooking on reducing the health risk, the concentrations of total arsenic in raw and cooked rice were measured. Raw rice of two rainfed rice varieties was purchased from market of Dhaka, Bangladesh in 2015. Minikit is a long slender grained popular rice variety in Bangladesh while Kataribhogh is a fine grained aromatic rice which is famous for its aroma and texture. One hundred grams of raw rice was washed with Milli-Q water three times. Then, raw rice was cooked with Milli-Q water: grain ratio of 5:1 in an iron pan covered with lid and the excess water after cooking was decanted. Cooked rice was freeze-dried and ground for arsenic analysis. A microwave digestion was used to digest the rice samples for analysis. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The arsenic concentrations in raw rice of Minikit and Kataribhogh in this study were 0.123−0.153 µg g−1 and 0.611−0.783 µg g−1, respectively. On the other hand, the total arsenic contents in cooked rice of Minikit and Kataribhogh were 0.115 ± 0.004 µg g−1 and 0.386 ± 0.004 µg g−1, respectively. There was 17% and 46% reduction of arsenic due to washing and cooking of Minikit and Kataribhogh rice, respectively. Based on the concentration of arsenic in raw and cooked rice, the carcinogenic risk of arsenic via rice ingestion was estimated. The estimated risk of arsenic with cooked rice was 1.2 × 10−5 and 4.1 × 10−5 while that of raw rice was 1.5 × 10−5 and 7.7 × 10−5 for Minikit and Kataribhogh rice, respectively. The results of this study revealed that health risk assessment on the basis of arsenic content of raw rice would be overestimated than the actual health risk.