Adsorption studies and the removal of dissolved metals using pyrolusite as adsorbent

The adsorption of metals from aqueous solutions of Pb²⁺, Zn²⁺ and Mg²⁺ on naturally occurring pyrolusite have been studied. The chemical stability of the pyrolusite has been determined in NaOH, H₂SO₄, HNO₃, HCl, NaCl and NK₄Cl solutions of various concentrations. Adsorption of the metal ions followed the order Pb²⁺>Zn²⁺>Cd²⁺.The maximum adsorption of Pb²⁺ (100%) occurred at pH 7. the relation between the amount of Pb²⁺ adsorbed per unit weight of pyrolusite and the concentration of Pb²⁺ at equilibrium follows the Freundlich adsorption isotherm.The efficiency of pyrolusite has been demonstrated by removing lead from synthetic waste water. 100% and 96% removal of lead have been achieved from synthetic waste water containing 5 mg l^–1 and 120 mg l^–1 of Pb²⁺ respectively at pH 7. The results of these studies suggest that pyrolusite might provide an economical method for the removal of lead from industrial waste water.     

Numerical Simulation of Substrate‐Limited Degradation

This is the fourth in a series of papers through which the authors demonstrate how numerical transport modeling can assist the remediation design engineer in predicting the progress of enhanced reductive dechlorination remediation expected in the field. The first two papers dealt with the hydraulics of delivery and preliminary understanding of substrate‐limited degradation. The third paper compared a simulated substrate‐limited degradation progress to some early results measured at a site. Based on that comparison, conclusions were drawn regarding the differences in degradation rates between a field situation and laboratory studies, and inferences were made about the modeling steps needed to aid in designing enhanced reductive dechlorination systems. Since the presentation of those results, additional rounds of data have been obtained from the field, encompassing a more substantial range of degradation history. In this paper, the authors compare those results with the simulated predictions and present an illustrative example of design modification using the model. ©2016 Wiley Periodicals, Inc.     

Attributes of occupational injury among workers in the chemical industry and safety issues.

Case-study research was carried out with a view to find the attributes of occupational injury among workers in the chemical industry and to enhance safety issues. Injury data were collected and processed in terms of different variables, such as age, gender, skills, type of hazard, etc. Pareto analysis was then applied to find a pattern of occupational injury among the workers. The study revealed that 79.52% of the injured workers were in the 40-59 age group; 57.14% of accidents occurred during the 1st shift; 73.26% of accidents caused injury to hands, feet, chest to thigh, arms and eyes; and 70.93% of injuries were caused by pumps, carrying and lifting, vehicles, pipelines, valves, and grinding. Surprisingly, no one was injured in the group of temporary workers. The paper also provides specific suggestions followed by some action plans.     

A “justice” reading of the trans-national struggle of the people displaced by the Merowe Dam

ABSTRACT

This paper applies a “justice” lens to the struggle of the people displaced by the Merowe Dam in northern Sudan. Application of distributive, procedural, and representational aspects of justice exposes the dissatisfaction of the affected people with the government’s offer and execution of compensation. Consideration of social justice and the utility of norms in trans-national activism brings into sharp focus the difference in interests, and abilities of the many actors involved, and highlights the government’s tactics to divide the communities, and the social divisions sown. As the struggle develops, justice claims are seen to change towards less material issues, suggesting that an expanded and dynamic conception of justice is more helpful than narrow or time-bound conceptions. The findings are of relevance to communities facing possible displacement from dams planned nearby, not least of all for the insight provided on the effectiveness of different tactics in the struggle.     

Production of surfactin using pentose carbohydrate by Bacillus subtilis

Interest in microbial surfactants has been steadily increasing in recent years due to their diversity, mass production possibility, selectivity, performance under extreme conditions and potential applications in environmental protection. In this study two pentose sugars (xylose and arabinose) were investigated for the submerged fermentation (SmF) of Bacillus subtilis in surfactant production medium for bio-surfactant surfactin production. An excellent vegetative growth of B. subtilis (× 10¹⁰ CFU/mL) was observed for xylose and arabinose containing medium which were comparable to glucose supplemented medium. Low growth (× 10⁸ CFU/mL) was found when medium was not supplemented with any of the sugars. Surfactin production in xylose, arabinose and glucose containing medium was 2700, 2600 and 2000 mg/L, respectively, whereas, medium without any sugar showed low surfactin (700 mg/L) production. These results clearly indicate the effect of pentose sugars on production of surfactin. Gradual depletion of the xylose and arabinose were confirmed by HPLC analysis during the growth phase of the strain that ultimately produced the surfactin.     

Production of iturin A homologues under different culture conditions

Iturin A is a cyclic lipopeptide antibiotic and eight different kinds of iturin A have been reported based on its alkyl side chains. As iturin A is a promising biocontrol agent, total production of iturin A was tried to enhance and comparative production of its homologues was investigated by using different nitrogen and carbon sources. When Polypepton S and defatted soybean meal were used, total production as well as the ratio of the iturin A homologues were similar. However, production of iturin A was relatively lower and also the ratio of the iturin A homologues was different when Polypepton was used, where A2 was decreased and A4 was increased. Production ratio of the iturin A homologues was similar for the carbon sources like maltose, mannitol, sucrose and starch but relative production of iturin A2 was much enhanced compared to A3 when lactose or galactose was used. Interestingly production ratio of A4 was increased and A2 and A3 were decreased when no additional carbon source was used, and similar tendency was observed in the homologue ratio with glucose and fructose. Production of iturin A homologue A6 was significantly increased whereas A2 and A3 were decreased when defatted rapeseed cake was used. Utilization of different amino acids did not show significant differences in their production of the iturin A homologues. Oxygen supply found to be the factor affecting the production of iturin A homologues when it was investigated in a varied culture volume size and shaking speed. A2 found to be increased with increased oxygen supply where the production of A3 was affected inversely.     

Potentially toxic elements in soil of the Khyber Pakhtunkhwa province and Tribal areas,Pakistan: evaluation for human and ecological risk assessment

Environmental Geochemistry and Health - Potentially toxic elements (PTEs) contaminations in the soil ecosystem are considered as extremely hazardous due to toxicity, persistence and bioaccumulative...     

People’s dependency on forest resources and contributions of forests to the livelihoods: a case study in Chittagong Hill Tracts (CHT) of Bangladesh

The study was conducted to investigate people’s forest dependency and contributions of forests to the livelihoods in the three hill districts of Chittagong Hill Tracts (CHT), Bangladesh. The study revealed that forest resources contribute significantly to rural community’s livelihoods and economic well-being. Using generalized logistic regressions, this study has also investigated the socioeconomic factors that affect people’s dependency on forest resources of CHT. The study revealed that people’s income from forest and forest-related occupation was positively aligned with their forest dependency. However, their education level significantly reduced their dependency on forest resources. Thus, educating the forest-dependent people and supporting alternative income generation activities should be appreciated for effective forest management in CHT. This study will be helpful to forest and environmental policy makers for CHT.     

Vertical distribution and contamination assessment of heavy metals in sediment cores of ship breaking area of Bangladesh

Environmental Geochemistry and Health - Vertical heavy metal profiling reflects the history of the deposition of metals and helps to understand the characteristics of accumulation in various layers...     

Particulate matters and gaseous pollutants in indoor environment and Association of ultra-fine particulate matters (PM1) with lung function

Environmental Science and Pollution Research - Real-time particulate matters (PM1, PM2.5, PM4, PM7, PM10, and TSP) with AEROCET 531S (USA), gaseous pollutants (NO2 and TVOC) with Aeroquel 500 gas...