Packed-bed Continuous Reactor Research Articles

Bio-composite of Fe-sludge biochar immobilized with Bacillus Sp. in packed column for bio-adsorption of Methylene blue in a hybrid treatment system: Isotherm and kinetic evaluation

The present study highlights the potential of bio-composite of Fe-sludge biochar and Bacillus sp for decolorization of Methylene blue (MB) dye. The Packed Bed Continuous Reactor (PBCR) hybrid system was containing bio-composite of Fe-sludge biochar with an ultraviolet system containing 600 mg ⋅L−1 MB dye. PBCR treated effluent was passed through the immobilized Bacillus sp. cells for biodegradation. The adsorption capacity of Fe-sludge biochar was 29.13 mg/g after 5 treatment cycles in PBCR. The kinetics parameters for pseudo-first-order, K1 and R2 were found to be 0.007 min −1 and 0.95; pseudo-second-order K2 and R2 were 1.69 g/mg/min and 1.0, respectively for bio-composite of Fe-sludge biochar Adsorption isotherm parameters values for Langmuir (KL), Freundlich (KF), and R2 were found to be 0.0366 L mg −1, 0.685 mg g-1 and 0.37 and 0.79, respectively. The Monod growth kinetic parameters Ks, μmax/Ks and μmax were found 41.3 mg day −1, 0.0103 mg day −1, and 0.426 day −1 respectively. Fe-sludge biochar immobilized with bacteria cell shows higher removal efficiency of MB dye in comparison to free bacterial cells system. Adsorption using the hybrid process (engineered biochar + bacteria) could be more effective and low-cost green approach for the organic pollutants removal from the industrial effluent.

Enzymatic synthesis of ethyl esters from waste oil using mixtures of lipases in a plug-flow packed-bed continuous reactor.

This work describes the continuous synthesis of ethyl esters via enzymatic catalysis on a packed-bed continuous reactor, using mixtures of immobilized lipases (combi-lipases) of Candida antarctica (CALB), Thermomyces lanuginosus (TLL), and Rhizomucor miehei (RML). The influence of the addition of glass beads to the reactor bed, evaluation of the use of different solvents, and flow rate on reaction conditions was studied. All experiments were conducted using the best combination of lipases according to the fatty acid composition of the waste oil (combi-lipase composition: 40% of TLL, 35% of CALB, and 25% of RML) and soybean oil (combi-lipase composition: 22.5% of TLL, 50% of CALB, and 27.5% of RML). The best general reaction conditions were found to be using tert-butanol as solvent, and the flow rate of 0.08mLmin-1 . The combi-lipase reactors operating at steady state for over 30 days (720 h), kept conversion yields of ∼50%, with average productivity of 1.94 gethyl esters<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mi>g</mml:mi></mml:mrow><mml:mrow><mml:mtext>substrate</mml:mtext></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msubsup></mml:math> h-1 , regardless of the type of oil in use. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:952-959, 2018.

A feasibility study on photocatalytic degradation of methyl benzene using N doped TiO&lt;SUB align="right"&gt;2 nanoparticles

Volatile organic compounds (VOCs) are common hazardous pollutants found in air, water and soil. In the present study, laboratory designed batch and continuous photocatalytic degradation of methyl benzene, a major contaminant in water, is demonstrated using N doped TiO2 photocatalyst. The N doped TiO2 photocatalyst was prepared under the sol-gel techniques and characterised by different analytic techniques. Treatment efficiency of N doped TiO2 photocatalyst was carried out under the visible-radiation source using laboratory scale reactors such as batch reactor, fluidised moving bed reactor and packed column bed reactor. The effects of parameters viz., photocatalyst concentration, recovery and reusability of the photocatalyst on degradation of VOCs were studied. Simulated methyl benzene in water showed maximum degradation efficiency of 74% in fluidised moving bed reactor; in the packed bed continuous reactor and batch reactor the values were 40% and 50%, respectively.

Steady-state inhibition model for the biodegradation of sulfonated amines in a packed bed reactor

Aromatic amines are important industrial products having in their molecular structure one or more aromatic rings. These are used as precursors for the synthesis of dyes, adhesives, pesticides, rubber, fertilizers and surfactants. The aromatic amines are common constituents of industrial effluents, generated mostly by the degradation of azo dyes. Several of them are a threat to human health because they can by toxic, allergenic, mutagenic or carcinogenic. The most common are benzenesulfonic amines, such as 4-ABS (4-aminobenzene sulfonic acid) and naphthalene sulfonic amines, such as 4-ANS (4-amino naphthalene sulfonic acid). Sometimes, the mixtures of toxic compounds are more toxic or inhibitory than the individual compounds, even for microorganisms capable of degrading them. Therefore, the aim of this study was to evaluate the degradation of the mixture 4-ANS plus 4-ABS by a bacterial community immobilized in fragments of volcanic stone, using a packed bed continuous reactor. In this reactor, the amines loading rates were varied from 5.5 up to 69 mg L(-1) h(-1). The removal of the amines was determined by high-performance liquid chromatography and chemical oxygen demand. With this information, we have studied the substrate inhibition of the removal rate of the aromatic amines during the degradation of the mixture of sulfonated aromatic amines by the immobilized microorganisms. Experimental results were fitted to parabolic, hyperbolic and linear inhibition models. The model that best characterizes the inhibition of the specific degradation rate in the biofilm reactor was a parabolic model with values of RXM=58.15±7.95 mg (10(9) cells h)(-1), Ks=0.73±0.31 mg L(-1), Sm=89.14±5.43 mg L(-1) and the exponent m=5. From the microbial community obtained, six cultivable bacterial strains were isolated and identified by sequencing their 16S rDNA genes. The strains belong to the genera Variovorax, Pseudomonas, Bacillus, Arthrobacter, Nocardioides and Microbacterium. This microbial consortium could use the mixture of aromatic amines as sources of carbon, nitrogen, energy and sulfur.