Potential of Biochar as Cost Effective Adsorbent in Removal of Heavy Metals Ions From Aqueous Phase: A Mini Review

Due to industrialization and increasing population, wastewater treatment has become a big challenge. There are numerous techniques such as ion-exchange, adsorption, membrane filtration, coagulation, flocculation, floating and electrochemical approach developed for the remediation of contaminants from wastewater. But, now it is necessary to develop an approach which should has high efficiency, less expensive and environmental friendly, so that limitation of existing techniques can be overcome. Recent developments of biochar have attracted the researchers into this area. Different methods are discovered to synthesized biochar for the removal of pollutants from wastewater. In this review, biochar are elaborated and critically discussed which have reported for the removal of metallic pollutants present in waste water

Eco-management of Wastewater by ZESTP

In present study, an evaluation of ZESTP (Zero Energy Sewage Treatment Plant) has been described as an alternative solution of sewage water treatment. This system has become widely famous because of having great absorption efficiencyof nutrients, simple construction and maintenance, relatively less costly as well as a strong process. After treatment of sewage water, the level of dissolve oxygen was increased up to 73% due to the enhanced numbers of photosynthetic organisms. Some aquatic macrophytes such as Eichhornia crassipes (Mart.) Solms, Pistia stratiotes L. and Hydrilla verticillata Casp were used in ZESTP for waste water treatment based on phytoremediation. ZESTP could reduce the around 84% turbidity, 46% electrical conductivity, 43% salinity, 74% acidity, 69% free CO2, 73% BOD, 44% COD, 70% suspended solids, 62% total hardness, 71% chloride, 59% cadmium, 51% iron, and 71% copper from the waste water. Naturally, some plants have capability are to retain and/or remove fatal chemicals which are present in sewage water. Moreover, macrophytes based ZESTP is a cost effective and an eco-friendly technique of sewage water treatment

Hyperspectral sensing for turbid water quality monitoring in freshwater rivers: Empirical relationship between reflectance and turbidity and total solids

Total suspended solid (TSS) is an important water quality parameter. This study was conducted to test the feasibility of the band combination of hyperspectral sensing for inland turbid water monitoring in Taiwan. The field spectral reflectance in the Wu river basin of Taiwan was measured with a spectroradiometer; the water samples were collected from the different sites of the Wu river basin and some water quality parameters were analyzed on the sites (in situ) as well as brought to the laboratory for further analysis. To obtain the data set for this study, 160 in situ sample observations were carried out during campaigns from August to December, 2005. The water quality results were correlated with the reflectivity to determine the spectral characteristics and their relationship with turbidity and TSS. Furthermore, multiple-regression (MR) and artificial neural network (ANN) were used to model the transformation function between TSS concentration and turbidity levels of stream water, and the radiance measured by the spectroradiometer. The value of the turbidity and TSS correlation coefficient was 0.766, which implies that turbidity is significantly related to TSS in the Wu river basin. The results indicated that TSS and turbidity are positively correlated in a significant way across the entire spectrum, when TSS concentration and turbidity levels were under 800 mg·L(-1) and 600 NTU, respectively. Optimal wavelengths for the measurements of TSS and turbidity are found in the 700 and 900 nm range, respectively. Based on the results, better accuracy was obtained only when the ranges of turbidity and TSS concentration were less than 800 mg·L(-1) and less than 600 NTU, respectively and used rather than using whole dataset (R(2) = 0.93 versus 0.88 for turbidity and R(2) = 0.83 versus 0.58 for TSS). On the other hand, the ANN approach can improve the TSS retrieval using MR. The accuracy of TSS estimation applying ANN (R(2) = 0.66) was better than with the MR approach (R(2) = 0.58), as expected due to the nonlinear nature of the transformation model

Facile Synthesis and Characterization of N-Doped TiO2 Photocatalyst and Its Visible-Light Activity for Photo-Oxidation of Ethylene

A facile wet chemical method was adopted for preparing highly photoactive nitrogen doped TiO2 (N-TiO2) powders with visible responsive capability, which could be achieved by the hydrolysis of titanium isopropoxide (TTIP) in the ammonium hydroxide precursor solution in various concentrations and then calcined at different temperatures. The N-TiO2 powders were characterized, and the photocatalytic activity was evaluated for the photocatalytic oxidation of ethylene gas under visible light irradiation to optimize the synthesizing conditions of N-TiO2 catalyst. The N-TiO2 photocatalytic powders were calcined in a range of temperatures from 300 to 600°C and obviously found to have greater photocatalytic activities than commercial TiO2 P25. The strong absorption in the visible light region could be ascribed to good crystallization and adapted sinter temperature of as prepared sample. XPS test demonstrated that the N was doped into TiO2 lattice and made an interstitial formation (Ti-O-N), and N doping also retarded the phase transformation from anatase to rutile as well. The N-TiO2 catalyst prepared with 150 mL ammonium hydroxide added and calcined at 500°C showed the best photocatalytic activity. The experimental results also proved the enhanced photoactivity of N-TiO2 material depends on the synthesizing conditions