Lab-scale continuous flow studies for comparative biosorption of cadmium (II) on untreated and xanthated Ficus religiosa biomass.

The present studies report the use of an ecofriendly biomass Ficus religiosa in untreated (UFR) and xanthate treated (XFR) forms for the Cd (II) ions removal in a fixed bed column. FTIR, SEM-EDS, BET surface area, and elemental analysis (CHNS) techniques were used to characterize the biosorbents. The acquired data supported FTIR findings regarding the nature of functional groups present in the materials. Packed bed continuous flow studies explored the effects of various parameters such as Cd (II) ion concentration (100 mg/L-300 mg/L), bed heights (5 cm-30 cm), pH (3-5), at a constant linear flow rate (~1.13 cm/min). The obtained S-shaped breakthrough curves indicated the efficiency of the packed bed for the Cd (II) removal. Breakthrough time and exhaust times increased (67.5 min-390 min and 292.5 min-1852.5 min) (97.5 min-442.5 min and 345 min-1920 min) for unmodified and modified respectively with bed heights. The BDST, Thomas, and Yoon-Nelson models were used to evaluate the experimental results. The Yoon-Nelson model describes the breakthrough data more efficiently compared to other models. Under similar conditions, the modified material exhibited 400% increased capacity (55.20 mg/g) than that of unmodified material (13.33 mg/g). Thus, xanthate modification significantly enhanced the capacity for Cd (II) ions from aqueous solutions. PRACTITIONER POINTS: Xanthate modification of Ficus religiosa is an environmentally friendly process. Modified and unmodified materials were utilized for Cd (II) removal in fixed bed column process which is industrially viable process. Low inlet Cd (II) concentration at pH 5 and higher bed height favored the continuous flow process at fixed flow rate. Modification caused an increase of about 400% in the capacity of material.

Forensic Discrimination Potential of Blue, Black, Green, and Red Colored Fountain Pen Inks Commercially Used in Pakistan, by UV/Visible Spectroscopy, Thin Layer Chromatography, and Fourier Transform Infrared Spectroscopy.

Examination and comparison of fountain pen inks are very important in forensic questioned documents examination in developing countries where the chances of fraud are greater in cases of cheques, marriage papers, entry of birth and death, etc. In this study, fountain pen inks of blue, black, green, and red colours that are commercially used in Pakistan have been discriminated by UV-Vis spectroscopy, TLC, and FTIR spectroscopy. We have calculated and compared the results in terms of discriminating power. UV/Visible Spectroscopy of fountain pen inks of different brands showed different composition despite their similar colours. TLC was effectively used to differentiate between the colored components of inks. FTIR results showed that each brand could be distinguished by studying the pattern of their absorption spectra that appeared due to the presence of different functional groups. On the basis of combined results of UV-VIS, TLC, and FTIR, the DP was found from 0.73-0.8 for blue, 0.80-1.0 for black, 0.5-1.0 for green, and 1.0 for red colored fountain pen inks. Overall, this study demonstrated the elevated worth of analysis of fountain pen inks commercially used in Pakistan as the study for fountain pen inks, while not very common, remains an interesting target study.

Biosorption of Pb(II) and Cr(III) from aqueous solutions: breakthrough curves and modeling studies.

The sorption capacity parameters obtained for batch studies provide useful information about biosorption system. However, such data fail to explain the process under continuous-flow conditions. The present study is an attempt to explore the biosorption of Pb(II) and Cr(III) by straw from local wheat (Triticum aestivum). The biosorbent has been characterized by using Fourier transform infrared spectroscopy and surface area and elemental analyses and found to be porous and polyfunctional. S-shaped breakthrough curves were obtained at different column heights for the both metal ions. Various breakthrough parameters and saturation times have been determined. The column data have been successfully used to study the Bohart-Adams' bed depth service time (BDST) model and Yoon and Nelson's model. It was found that BDST model quite efficiently explained the whole column data whereas Yoon and Nelson model could explain it below 90% breakthrough concentration. The predicted and calculated BDST parameters were in agreement with each other. Yoon and Nelson's constant decreased with an increase in the column height for both metal ions. Effect of change in flow rate on the Pb(II) biosorption has also been discussed with respect to BDST approach.

Source, concentration, and distribution of elemental mercury in the atmosphere in Toronto, Canada.

Atmospheric gaseous elemental mercury [GEM] at 1.8, 4, and 59 m above ground, in parking lots, and in indoor and outdoor air was measured in Toronto City, Canada from May 2008-July 2009. The average GEM value at 1.8 m was 1.89 ± 0.62 ng m(-3). The GEM values increased with elevation. The average GEM in underground parking lots ranged from 1.37 to 7.86 ng m(-3) and was higher than those observed from the surface parking lots. The GEM in the indoor air ranged from 1.21 to 28.50 ng m(-3), was higher in the laboratories than in the offices, and was much higher than that in the outdoor air. All these indicate that buildings serve as sources of mercury to the urban atmosphere. More studies are needed to estimate the contribution of urban areas to the atmospheric mercury budget and the impact of indoor air on outdoor air quality and human health.

Antifungal compounds from Melia azedarach leaves for management of Ascochyta rabiei, the cause of chickpea blight.

The antifungal activity of Melia azedarach L. leaves was investigated against Ascochyta rabiei (Pass.) Lab., the cause of destructive blight disease of chickpea (Cicer arietinum L.). Bioassay guided fractionation revealed that the chloroform fraction of the methanolic extract of M. azedarach leaves was highly effective against A. rabiei. Six compounds, namely ß-sitosterol (1), ß-amyrin (2), ursolic acid (3), benzoic acid (4), 3,5 dimethoxybenzoic acid (5) and maesol (6) were isolated from the chloroform fraction through column chromatography. The in vitro antifungal activity of compounds 2-5 was evaluated against A. rabiei. A commercial fungicide, mancozeb, was used as a positive control. Different concentrations of mancozeb and the isolated compounds, ranging from 0.0039 to 4 mg mL(-1), were used in the antifungal bioassay, and data regarding minimum inhibitory concentration (MIC) was recorded 24, 48 and 72 h after incubation. All concentrations of mancozeb inhibited the fungal spore germination at all three incubation periods. The tested compounds exhibited variable antifungal activity against the target fungal pathogens. All compounds showed their highest antifungal activity after 24 h of incubation. Compound 2 was found to be the most effective, with an MIC of 0.0156 mg mL(-1), followed by compounds 3, 4 and 5, with MIC values of 0.0312, 0.25 and 0.125 mg mL(-1), respectively.

Biosorption of heavy metal ions using wheat based biosorbents--a review of the recent literature.

Conventional technologies for the removal/remediation of toxic metal ions from wastewaters are proving expensive due to non-regenerable materials used and high costs. Biosorption is emerging as a technique offering the use of economical alternate biological materials for the purpose. Functional groups like carboxyl, hydroxyl, sulphydryl and amido present in these biomaterials, make it possible for them to attach metal ions from waters. Every year, large amounts of straw and bran from Triticum aestivum (wheat), a major food crop of the world, are produced as by-products/waste materials. The purpose of this article is to review rather scattered information on the utilization of straw and bran for the removal/minimization of metal ions from waters. High efficiency, high biosorption capacity, cost-effectiveness and renewability are the important parameters making these materials as economical alternatives for metal removal and waste remediation. Applications of available adsorption and kinetic models as well as influences of change in temperature and pH of medium on metal biosorption by wheat straw and wheat bran are reviewed. The biosorption mechanism has been found to be quite complex. It comprises a number of phenomena including adsorption, surface precipitation, ion-exchange and complexation.

Impact of transport and industrial emissions on the ambient air quality of Lahore City, Pakistan.

Lahore's population is growing at a rate of 4% a year. It is widely perceived that because of this rapid growth, the level of services provided to the city's 7 million inhabitants has substantially deteriorated. This study presents the finding of ambient air quality monitoring carried out in Lahore City, Pakistan. The ambient air quality was monitored for criteria pollutants carbon monoxide (CO), nitrogen dioxide (NO(2)), sulfur dioxide (SO(2)), ozone (O(3)), particulate matter (TSP and PM(10)), lead (Pb), and noise level at ten different locations of the city. The sampling locations were selected in a way to draw a representative profile of air quality, covering both newly developed as well as highly congested urban centers. The sulfur dioxide, lead, and suspended particulate concentration was found very high as compared to the ambient air quality standards of US Environmental Protection Agency and WHO guidelines. The 24-h average noise was exceeding the WHO limits at majority of the locations. The study presents the severity of air pollution in Lahore City, and findings would help city management to develop monitoring and mitigation measures to improve the air quality of the city.

Gaseous and particulate emissions from thermal power plants operating on different technologies.

This paper presents the assessment of gaseous and particulate emissions from thermal power plants operating on different combustion technologies. Four thermal power plants operating on heavy furnace oil were selected for the study, among which three were based on diesel engine technology, while the fourth plant was based on oil-fired steam turbine technology. The stack emissions were monitored for critical air pollutants carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur dioxide, particulate matter, lead, and mercury. The pollutant emissions were measured at optimum load conditions for a period of 6 months with an interval of 1 month. The results of stack emissions were compared with National Environmental Quality Standards of Pakistan and World Bank guidelines for thermal power plants, and few parameters were found higher than the permissible limits of emissions. It was observed that the emissions carbon monoxide, oxides of nitrogen, and particulate matters from diesel engine-based power plants were comparatively higher than the turbine-based power plants. The emissions of sulfur dioxide were high in all the plants, even the plants with different technologies, which was mainly due to high sulfur contents in fuel.

Air pollution due to traffic, air quality monitoring along three sections of National Highway N-5, Pakistan.

Transportation system has contributed significantly to the development of human civilization; on the other hand it has an enormous impact on the ambient air quality in several ways. In this paper the air and noise pollution at selected sites along three sections of National Highway was monitored. Pakistan National Highway Authority has started a Highway Improvement program for rehabilitations and maintenance of National highways to improve the traffic flows, and would ultimately improve the air quality along highways. The ambient air quality and noise level was monitored at nine different locations along these sections of highways to quantify the air pollution. The duration of monitoring at individual location was 72 h. The most of the sampling points were near the urban or village population, schools or hospitals, in order to quantify the air pollution at most affected locations along these roads. A database consisting of information regarding the source of emission, local metrology and air quality may be created to assess the profile of air quality in the area.

Azadirachata indicum (Neem): an effective biosorbent for the removal of lead (II) from aqueous solutions.

Laboratory batch experiments with Azadirachata indicum indicated that this population had an excellent ability to bind lead (II) from its aqueous solution. The experiments carried out examined pH, biomass quantity, time of contact, and temperature dependency. Under optimum conditions, the removal of lead (II) was found to be around 95%. Column experiments were performed to examine the binding of lead (II) to silica-immobilized biomass under flow conditions. During this, a slight decrease in the pH of the effluents was also observed, implying an ion-exchange mechanism for metal binding.