NOPR Community:

Biodiesel synthesis and bioreactor design – An overview

Wed, 01 Nov 2017 00:00:00 GMT

Title: Biodiesel synthesis and bioreactor design – An overview Authors: De, Tripti; Sikder, Jaya; Narayanan, C M Abstract: Biodiesel, an alternate, renewable, environment-friendly engine fuel, is making significant contribution to the world energy demand, particularly in the light of the diminishing petroleum reserves. In this paper, biodiesel synthesis from different feedstocks and use of different types of catalysts (both homogeneous and heterogeneous) has been reviewed. These feedstocks have been compared with respect to availability (yield of oil per unit area of cultivation), ease and fastness of transesterification, yield and purity of produced biodiesel. The comparison between homogeneous and heterogeneous catalysts including enzyme catalysts and relative superiority of each have been analysed and highlighted with respect to catalyst activity, formation of uncontaminated product and cost of downstream processing. The design features of different types of industrial bioreactors such as fluidised bed, semifluidised bed, diverging–converging fluidised bed and inverse fluidised bed reactors have been surveyed. Recommendations for future investigations have also been presented in this paper. Page(s): 575-592

Adsorption of hexavalent chromium (Cr(VI)) from wastewater using novel chitosan/halloysite clay nanocomposite films

Wed, 01 Nov 2017 00:00:00 GMT

Title: Adsorption of hexavalent chromium (Cr(VI)) from wastewater using novel chitosan/halloysite clay nanocomposite films Authors: Padmavathy, K S; Murali, Amith; Madhu, G; Sahoo, Deepak Kumar Abstract: Nano composite films have been prepared in the laboratory by impregnating halloysitenanoclay on chitosan matrix. The functional groups present in the composite films have been investigated using Fourier transform infrared spectroscopy (FTIR) and morphological structure of the synthesized films are analysed using scanning electron microscopy (SEM). Thermo gravimetric analyser (TGA) is used for investigating the thermal stability of the composite. The films are used for adsorption of hexavalent chromium from wastewater. Optimum pH for adsorption is 3.0 and all other experiments are conducted at pH 3.0. It has been observed that adsorbent dosage required is very less when compared to pure chitosan as adsorbent. The adsorption capacity is also very high when compared with pure chitosan for removal of Cr (VI) under the same conditions. The equilibrium studies have been conducted and data is fitted to the Langmuir equation. The kinetic studies reveal that the adsorption mechanism is pseudo second order. The study shows that the chitosan/halloysite clay can be used as a promising adsorbent for hexavalent chromium uptake from wastewater. Page(s): 593-600

Adsorption of Cd and Pb metal ions onto chelating resin and their application in removal of lead from battery factory wastewaters

Wed, 01 Nov 2017 00:00:00 GMT

Title: Adsorption of Cd and Pb metal ions onto chelating resin and their application in removal of lead from battery factory wastewaters Authors: Addala, Abdelhamid; Belattar, Noureddine Abstract: Lead is one of the most used metals in various factory activities. The contamination of soil and water with the metal has become a real or major environmental and public health problem or concern. Therefore, removal this toxic metal from wastewaters is a great challenge to protect environment and people. This study aims to assess adsorbing properties by batch procedure of a chelating ion exchange functionalized by iminodiacetic acid group toward Pb and Cd by varying the concentration of these metals at different contact times and at a given pH. In the second step, this adsorbent support is used in dynamic condition in a column for the removal of Pb particularly from effluents from an industrial unit. Finally, the exchange material, packed in bed, is regenerated in order to establish its reusability and efficiency in removing process. The adsorption rate of Pb and Cd onto the chelating adsorbent increases as the initial content and time contact increase and the maximum adsorption capacity is found to be 137.40 and 90.40 mg/g at the plateau of saturation, respectively. In a column, the adsorbing support or material reduce totally the concentration of loaded Pb in effluents during the two first cycles. During the third cycle, the removal power is still good and the content of Pb in the washing is reduced from 22 mg/L to 0.014 mg/L which is lower than the law's discharge levels. The regeneration of the support is achieved by 10 volume bed of 1 M HCl during thirty minutes at least. These results demonstrate clearly the effectiveness of the chelating adsorbent in removing lead from the effluents of the factory and its reusability in numerous cycles after a regeneration stage. Page(s): 601-607

Synthesis of [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex and its application as DNA electrochemical sensor

Wed, 01 Nov 2017 00:00:00 GMT

Title: Synthesis of [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex and its application as DNA electrochemical sensor Authors: Song, Pan; She, Wen-Jie; Zhou, Tong; Yang, Tian-Lin; Ni, Gang; Na, Peng-Jun Abstract: The new tripod ligand [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex (Eu(pic)₃L) have been synthesized and characterized by TG-DSC, IR spectroscopy, UV-vis spectroscopy, elemental and molar conductance analysis. The experimental results show that the ligand forms the 1:1 complex with europium picrate. The results of UV-vis spectroscopy and cyclic voltammetry indicate that there are intercalation interaction between DNA and Eu(pic)₃L. When the Eu(pic)₃L is regarded as DNA hybridization probe and used in the study of DNA electrochemical sensor, no obvious electrochemical signal response could be found with Eu(pic)₃L under the effect of modified electrodes single-strand DNA testing. However, obvious electrochemical signal response is found when it is under the effect of double-stranded DNA testing. It indicates that the biosensor can discriminate well between the complementary sequences from the base-mismatched and the non-complementary sequences. So Eu(pic)₃L can be used as a biosensor to discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. Page(s): 608-615