Current Environmental Engineering - Volume 3, Issue 3, 2016

The evolution of science and technology has been shifted towards nano science and technology as the demand and application of the nano technology is growing very rapidly. With respect to this, metal oxide nano materials play very important role in various applications. Titanium dioxide is one of the most important metal oxide nano materials, which is being broadly investigated because of its unique hydrophobic nature, photo catalytic, electrical and optical properties. These nanoparticles are prepared by different physical methods,chemical methods and biological methods. This review article is focussed on various synthesis methods empha- sising on biological methods because of their wide range of techniques availabilities. Various characterisation techniques for biologically synthesised nanoparticles are discussed. The characterization techniques performed are XRD, FESEM, AFM, PSA, EDX, TG-DTA, FTIR and UV- Visible for the study of crystal structure, mor- phology & size, surface properties, average particle size, elemental compositions, thermal properties, bond analysis and optical properties respectively. Applications of these nano particles are described in briefly such as solar cells, sensors, device fabrication, self-cleaning and environmental.

The purpose of this paper was to determine the content of arsenic, mercury elements in meat products and soil. The results showed that arsenic and mercury were concentrated in manure and were absorbed in minor quantities. In this paper, an adsorption model was established, to calculate the adsorption coefficient and transfer coefficient of arsenic and mercury. The reliability was observed to be more than 95% and the relative errors were within 0.5%.

Background: Rainfall events are known to be associated with the health of recreational water. Pathogens in recreational water may pose a risk to bathers and water users, including naturally occurring microorganisms as well as those that are present as a result of faecal pollution. This study aims to investigate whether rainfall events impact on the microbial quality of recreational water in Swan Canning estuary in Western Australia (WA) and to identify and propose effective management interventions. Methods: Compliance of water quality in recreational waters is assessed according to microbial water quality assessment categories (MACs) based on the 95th percentile of enterococci counts with the use of Enterotester TemplateTM. Results: Results indicate that the number of enterococci in the water rises along with increasing volumes of rainfall. Enterococci levels between 201 to 500 MPN/100ml are associated with rainfall ranging from 3-21mm and elevated enterococci levels over 700 MPN/100ml are associated with rainfall ranging from 12-35mm. Conclusion: A causal relationship between enterococci levels in recreational waters and rainfall events exists. Enterococci levels increase following rainfall events of 5mm and over in the majority of sampling sites along the Swan and Canning Rivers during five consecutive bathing seasons. Although environmental and faecal pol- lutions also contribute to recreational water quality, summer rainfall data has indicated that recreational water bodies experience periods of increased enterococci levels as rainfall volumes increase.

Background: At present scenario, there is the global issue due to the environment pollution caused by waste effluent bearing organic dyes such as Methyl Violet (MV) while getting mixed into the surface water. Such organic dye uses in industries like textile, paper, leather, food, pharmaceutical, cosmetics etc. is extensive leading to increase the contamination level and therefore, the removal of above dye is warranted by adopting suitable adsorbent to minimize the level of contamination. Present investigation accomplishes the study on removal of Methyl Violet (MV) dye from aqueous solution using low cost bioadsorbent as activated Phragmites karka (APK). Methods: The adsorbent APK was derived from Phragmites karka (PK) by charring with 25 % H2SO4 appears to be effective while enhancing MV loading efficiency than PK without activation. Operating variables such as contact time (1- 300 min), dye concentration (100-500 ppm), pH (2-11), sorbent dose (0.25-5.0 g) and temperature (293-333K) affecting to the adsorption of MV were studied. Adsorption Iso-therm, thermodynamics and kinetics are studied to ascertain the mechanism for the adsorption of MV on to APK. Results: Phase characterization study results of APK, MV loaded APK, and MV by FTIR and UV-VIS, respectively, ensured the adsorption process and mechanism. The maximum adsorption capacity of APK was resulted as 371.6 mg/g at ambient condition. The value of separation factor (RL) from Langmuir equation and Freundlich constant (n) indicated on favorability of adsorption. Positive value of ΔHo (4.9 kJ mol-1) indicated that adsorption was of endothermic and the negative value of ΔGo confirmed about feasibility of dye adsorption. Kinetics result revealed that adsorption of MV is of pseudo second-order ascertaining the chemisorptions type. Conclusion: The adsorption of MV with APK was critical with the influence of time, temperature and pH. The pH of the solution affects the surface charge of the adsorbent and the degree of ionization of adsorbate and adsorption was efficient at merely neutral pH range (pH-6.0). The adsorption of MV was also enhanced while increasing APK dose as well as initial MV concentration. Experimental equilibrium data showed best fit with Freundlich isotherm and Thermodynamic data showed the relevance on favoring the adsorption process. The present investigation ensured that APK can be used as an effective adsorbent while applying on purification of contaminated water / process aqueous solution.

Background: Acid mine / Copper mine drainage is one of the major source of Cu(II) ions. Acid mine or copper mine drainage occurs naturally within environments, but it is intensify by large scale earth disturbances found with copper mining or exhausted leach heap operations, as a result of generation of metal ions. These metal ions decomposed and produce an acidic waste stream which contains dissolved copper, iron, aluminium and zinc. Objective: The aim of this work was to study the equilibrium and performance of the Indion 730 (strong acid cation exchange resin). Indion 730 resins used as an adsorbent for removal of Cu (II) from Acid Mine Drainage (AMD). Present study also highlights the evaluation of sorption capacity of Indion730as an ion exchangers. A breakthrough curve was used to observe the effectiveness of packed bed column for removal of Cu (II) ions. The Profile of breakthrough curve and time intended for development of breakthrough curve are vital characteristics for determining the process and response of fixed bed column. Method: In the present study, the kinetics of fixed bed column has been tested for Clark’s model. Clark proposed a new simulation of the development of breakthrough curves. Clark model is based on the hypotheses that uses mass-transfer concept in combination with the Freundlich isotherm. Results: The result of this study has shown best testing of experimental breakthrough curves by the Clark kinetic equation has shown outstanding matching of experimental values with modeled curves. The linear method of solving of the equation gives matching values of parameters A and r, which suggests similar values of the sorption rate coefficient and removal capacity. Conclusion: The Clark kinetic models have been found to be suitable for the removal of Cu (II) on Indion 730 for various experimental conditions. On the basis of the premeditated parameters, the theoretical breakthrough curves have been plotted and compared with the experimental values.

In this research, the removal of methylparathion from aqueous solutions using ozonation process was assessed. Therefore, the response surface methodology and central composite design (CCD) of experiments were performed to evaluate the effects of individual operating variables and their interactions on the methylparathion (MP) removal with initial concentration of 1000 mg/L as fixed input parameter and the extent of MP degradation as responses. The effects of variables pH and reaction time were studied. Analysis of variance showed a high coefficient of determination value in the range of 0.9. The maximum degradation of methylparathion terms of MP removal (Y1), chemical oxygen demand (COD) removal (Y2) and total organic carbon (TOC) removal (Y3) were found to be 97 %, 92.4 % and 72 % respectively. p-nitrophenol and 3-methyl-2-(2-oxopropyl) furan were noted intermediates during the degradation. It was observed that optimum degradation of methylparathion can be successfully predicted statistically by CCD using ozonation.

Background: The detection of heavy metals in the environment is of great importance due to their high toxicity. Methods: A multi-step graft route was designed for anchoring thiosemicarbazide derivative (TSCD) groups onto the porous silicon (PS) surface. The reaction efficiency at each step functionalization was confirmed using FT-IR spectra, and the XPS analysis results confirmed the modification of thiosemicarbazide derivative. The morphology change of the modified PS was studied by AFM characterization. Results: The results display that the currents of Pb0 oxidation increase with the accumulated Pb2+ concentration and the TSCD-PS has a strongest sensitive to Pb2+ at pH = 4.0. The results display that the anodic peak current densities increase with the increasing Pb2+ concentration and they have a good fitting with a second order exponential function of I = -156exp(-1562[Pb2+]) - 260exp(-105 [Pb2+]) + 446 (R2 = 0.99). Conclusion: The TSCD-PS shows the property to determinate Pb2+ in aqueous solution, which demonstrates that the modified PS is expected to be a promising platform for detecting toxic metal ions.