Recovery of uranium from uranium refining waste water by using immobilized persimmon tannin

Some attempts were made to examine the practical conditions for uranium recovery from uranium refining waste water. The adsorbent was highly effective in recovering uranium. The uranium adsorption was affected by pH, temperature, and uranium concentration of the uranium refining waste water. The adsorbent also recovered uranium effectively in column system. It aquires better mechanical properties and can be used repeatedly in the uranium adsorption-desorption cycles.     

An advanced bioprocessing concept for the conversion of waste paper to ethanol

Applied Biochemistry and Biotechnology - Waste paper is a plentiful and low-cost lignocellulosic feed material that may represent the most direct way to penetrate the market with an advanced...     

Flow injection determination of ethanol in whole blood using immobilized enzymes

Enzymatic methods for the determination of ethanol in whole blood are proposed. They use different types of detection and flow injection analysis (FIA) modes: fluorometric detection (use of normal FIA and stopped-flow/FIA); amperometric detection by monitoring of NADH (use of normal amperometric and pulse mode) and with the aid of a coupled enzymatic reaction (2,6-dichlorophenolindophenol/diaphorase). Determination ranges between 0.1 and 30.0 μg/ml are obtained (which in all cases comprise the legal range of ethanol in blood), with good precision and sampling frequency. The sensitivity of the methods can be manipulated by changing the injected sample volume or the pH.     

Production of acetone butanol ethanol from degermed corn using Clostridium beijerinckii BA101

In this article we report on acetone butanol ethanol (ABE) fermentation characteristics of degermed corn when using Clostridium beijerinckii BA101. Recent economic studies suggested that recovery of germ from corn and hence corn oil would help to make the ABE fermentation process more economical. C. beijerinckii BA101 ferments corn mash efficiently to produce ABE under appropriate nutritional and environmental conditions. Corn mash contains germ/corn oil that is, possibly, ancillary to the production of butanol during the ABE fermentation process. Since the presence of corn oil is not a critical factor in solvent fermentation, it can be removed and this will allow for byproduct credit. Batch fermentation of degermed corn resulted in 8.93 g/L of total ABE production as compared with 24.80 g/L of total ABE when supplemented with P2 medium nutrients. During the course of the germ separation process, corn steeping is required prior to grinding and removing the germ. It is likely that some nutrients from the corn are leached out during the steeping process. This may reduce the rate of fermentation and impact the final concentration of butanol/ABE that can be achieved. Fermentation of degermed corn with corn steep liquor resulted in the production of 19.28 g/L of ABE.     

Production of citric acid using immobilized conidia of Aspergillus niger

Conidia of Aspergillus niger were immobilized in calcium alginate gel for the production of citric acid. First, the type of the preactivation medium, together with the preactivation period, was investigated. It was found that A. niger requires a 2-d preactivation period at a 0.05 g/L NH₄NO₃ concentration. Second, preactivated cells were used to determine the effects of nitrogen concentration and the flow rate of oxygen and air on the production of citric acid. Maximum citric acid production was attained with medium containing 0.01 g/L of NH₄NO₃. The rate of citric acid production in the nitrogenous medium was 33% higher when oxygen was used instead of air during the production phase. This corresponds to an increase of 85% when compared to production when neither oxygen nor air was fed into the system. In the nonnitrogenous medium citric acid concentration remained similar regardless of the use of air or oxygen. However, in the nonnitrogenous production medium, citric acid production was not influenced considerably when oxygen was used instead of air. The advantage of using immobilized cells is that production is achieved easily in the continuous system. Therefore, citric acid production was also tested using a packed-bed bioreactor, and an increase in productivity by a factor of 22 was achieved compared to the batch system.     

Separation of lead from high matrix electroless nickel plating waste solution using an ion-selective immobilized macrocycle system

Separation of trace levels of lead from concentrated-matrix electroless nickel plating (ENP) waste solutions is required to meet the increasingly stringent environmental regulations. A solid phase extraction (SPE) system using a molecular recognition technology (MRT) gel was used for the selective separation of trace levels of lead (Pb) from the waste discharge of ENP operations, followed by subsequent analysis with inductively coupled plasma optical emission spectrometry (ICP-OES). Two SPE-MRTs, AnaLig® Pb-01 and AnaLig® Pb-02, packed in 3 mL polypropylene cartridges were used to treat the synthetic metal-waste solutions that were used to simulate the typical metal mixture in ENP bath waste. The fortified solutions contained 100-1000 μg L^− 1 of Pb in an HNO₃ matrix with pre-added Ni, Cu and other interfering elements (1000 mg L^− 1). After the sample treatment, the SPE-MRT cartridges were washed with water and 0.1 M nitric acid, followed by elution with 0.03 M EDTA. The matrix elements (e.g., Ni, Cu) were completely removed at the washing step, while the ‘captured’ Pb was quantitatively eluted, as determined by ICP-OES measurements. The detection limit of the proposed method was 2.6 μg L^− 1. ‘Real’ samples from commercial ENP operations were used to assess the validity of this method, and almost quantitative Pb recovery was observed. The excellent Pb selectivity of the SPE-MRT system indicates the potential of the proposed technique for trace-level Pb separation from the Pb-containing high matrix aqueous waste discharge.     

Production of metakaolin from industrial cellulose waste

Research focused on the transformation and utilization of industrial wastes into products of commercial interest plays an increasingly important role. Residual pulp can become useful in the manufacture of different materials, providing high value to this waste and reducing its environmental impact when disposed of improperly in the environment. The main constituents of this waste are kaolin and calcium carbonate (CaCO₃). Starting from kaolin, metakaolin can be produced by calcination of the residue at 630?°C for 2?h in a rotary reactor with air flow, followed by solubilization with hydrochloric acid to remove the CaCO₃. The development of technological alternatives aimed at the reuse of certain wastes can result in applications of real economic interest to the chemical industry and ceramics and glass, which is the case in this study. The raw material and metakaolin obtained were analyzed by thermogravimetric analysis and derivative thermogravimetric analysis, X-ray diffraction, and X-ray fluorescence spectroscopy with promising results. This is because metakaolin was obtained free of contamination by other materials.     

Production of PHAs from agricultural waste material

Polyhydroxyalkanoates (PHAs) are biodegradable substitutes to fossil fuel plastics that can be produced from renewable raw materials such as saccharides, alcohols and low-molecular-weight fatty acids. They are completely degradable to carbon dioxide and water through natural microbiological mineralization. Consequently, neither their production nor their use or degradation have a negative ecological impact. By keeping closed the cycle of production and re-use, PHAs can enable at least part of the polymer-producing industry to switch from ecologically harmful end-of-the-pipe production methods towards sounder technologies. Up to now such polyesters have been produced biotechnologically from refined raw materials (e.g. glucose and sodium propionate), but they can as well be produced much cheaper from agricultural waste materials (e.g. molasses, maltose, glycerol phase from biodiesel production, whey), as long as these materials have a known composition and are available in appropriate quantities. Yield factors and specific rates for growth and PHA accumulation are shown for 3 strains of Alcaligenes latus for different agricultural waste carbon sources.     

Production of citronellyl acetate in a fed-batch system using immobilized lipase

Several reports exist in the literature citing the decrease in conversion rates of organic-phase catalytic synthesis reactions when acetic acid is present as a reaction component. This inhibition is thought to result from damage to either the hydration layer-protein interaction or the overall enzyme structure. In this work, the inhibitory effect of acetic acid on lipase enzyme activity was ameliorated by conducting syntheses under acetic acid-limiting conditions in a fed-batch system, resulting in higher product yields. Periodic additions of acetic acid at levels of 40 mM or less gave maximum yields of 65% conversion for the reaction of citronellol and acetic acid to form citronellyl acetate. The enzyme used was a fungal lipase fromMucor miehei, and was immobilized on macroporous synthetic resin (a Novo lipozyme Novo Nordisk, Denmark). These results represent a fourfold improvement over batch runs reported in the literature for direct esterification of terpene alcohol with acetic acid using lipozyme as a catalytic agent.     

Production of fumaric acid by immobilized rhizopus using rotary biofilm contactor

Rotary biofilm contactor (RBC) is a reactor consisting of plastic discs that act as supports for micro-organisms. The discs are mounted on a horizontal shaft and placed in a medium-containing vessel. During nitrogen-rich growth phase, mycelia ofRhizopus oryzae ATCC 20344 grew on and around the discs and formed the “biofilm” of self-immobilized cells on the surface of the plastic discs. During the fermentation phase, the discs are slowly rotated, and the biofilms are exposed to the medium and the air space, alternately. With RBC, in the presence of CaCO₃,Rhizopus biofilm consumes glucose and produces fumaric acid with a volumetric productivity of 3.78 g/L/h within 24 h. The volumetric productivity is about threefolds higher with RBC than with a stirred-tank fermenter with CaCO₃. Furthermore, the duration of fermentation is one-third of the stirred-tank system. The immobilized biofilm is active for over a 2-wk period with repetitive use without loss of activity.

     

Denitrification and removal of heavy metals from waste water by immobilized microorganisms

Pseudomonas fluorescens, immobilized on soft polyvinyl chloride granules containing up to 35% softeners as carbon source, was used for simultaneous removal of nitrate and heavy metals. In typical continuous column operation, a 100 mg/L nitrate input solution was reduced to a 20 mg/L output at a feeding rate of 1500 mL/h, with a capacity of 14 kg/day/m³, and with an efficiency of 79%. In the same column, Pb(NO₃)₂ concentration was reduced from 1.0 to 0.05−0.1 mg/L and ZnSO₄ concentration was reduced from 10 to 5 mg/L.Pseudomonas aeruginosa immobilized on an O₂ plasma-treated melt blown polypropylene web was used for removing 95% of a 1.7 nCi PuCl₄ activity from a nuclear plant waste water in a batch operation.     

Removal of malachite green by adsorbents from paper industry waste materials

The objective of this work is to study the removal of malachite green (MG) from water by adsorbents obtained from pyrolysis of two paper industry waste materials: one de-inking paper sludge (HP) and one organic sludge from virgin pulp mill (RT). Both adsorbents showed elevated MG removal. Maximum adsorption Q ₀ obtained by Langmuir equation was higher for the adsorbent from HP (HP-3, 982 mg/g) than RT (RT-3, 435 mg/g). However, K _L (Langmuir) and 1/n (Freundlich) indicated that affinity and intensity of adsorption is higher for the adsorbents from RT. Thermal analysis (TG, DTG and DTA) of adsorbents before and after MG removal was performed in N₂ atmosphere.     

Secondary fibrous materials from cardboard and paper production and consumption waste

Some information characterizing wastepaper, including utilization rates, technical data of different fiber grades, and waste paper processing technologies, is presented in the article. Wastepaper obtained from different sources such as cardboard and paper production, production of various goods (e.g. printing companies), and cardboard and paper consumption (e.g. household waste) is also described.     

Production of specific copolymers of polyhydroxyalkanoates from industrial waste

Polyhydroxyalkanoates, biodegradable plastics with the desired physical and chemical properties of conventional synthetic plastics, are extensively investigated. In this study, specific bacterial strains produced specific copolymers from food waste. Copolymers of HB and HV (poly[3-hydroxybutyrate-co-3-hydroxyvalerate]) were obtained using various ratios of butyric acid (C₄) and valeric acid (C₅) as carbon sources. The C₄ to C₅ ratio affected the melting points of the copolymers. Melting and glass transition temperatures and many other thermal properties are important parameters relative to in-service polymer applications. Higher ratios of butyrate to valerate gave higher melting points. When a mixed culture of activated sludge was employed to produce copolymers using food wastes as nutrients, the obtained copolymers showed various monomer compositions. Copolymers with a higher portion of HV were obtained using soy waste; copolymers with less HV were obtained using malt wastes. Pure strains, (i.e., Alcaligenes latus DSM 1122, and DSM 1124, Staphylococcus spp., Klebsiella spp.) produced specific copolymers from food waste. Only Klebsiella spp. produced different copolymers; the ratios of HB:HV were 93:7 and 79:21 from malt waste and soy waste, respectively. The other strains produced polymers of 100% HB. Selecting industrial food wastes as carbon sources can further reduce the cost of producing copolymers. Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis The University Grants Committee Area of Excellence Scheme, Hong Kong     

Continuous-flow analysis for ethanol with immobilized alcohol dehydrogenase

Alcohol dehydrogenase is immobilized by reaction with glutaraldehyde onto silica gel, which is packed in a column in a flow system. Ethanol (0.1–5 mmol) is determined by catalysis of the reaction with NAD⁺, the NADH produced being detected amperometrically. The reproducibility is ca. 1%.     

Bioconversion of mixed solids waste to ethanol

A mixed solids waste (MSW) feedstock, comprising construction lumber waste (35% oven-dry basis), alm ond treeprunings (20%), wheat straw (20%), office waste paper (12.5%), and newsprint (12.5%), was converted to ethanol via dilute-acid pretreatment followed by enzymatic hydrolysis and yeast fermentation. The MSW was pretreated with dilute sulfuricacid (0.4% w/w) at 210°C for 3 min in a 4-L stea mexplosion reactor, then washed with water to recover the solubilized hemicellulose. The digestibility of water-washed, pretreated MSW was 90% in batch enzymatic hydrolysis at 66 FPU/g cellulose. Using an enzyme-recycle bioreactor system, greater than 90% cellulose hydrolysis was achieved at a net enzyme loading of about 10 FPU/g cellulose. Enzyme recycling using mebrane filtration and a fed-batch fermentation technique is a promising option for significantly reducing the cost of enzyme in cellulose hydrolysis. The hexosesugars were readily fermentable using a Saccharomyces cerevisiae yeast strain that was adapted to the hydrolysate. Solid residue after enzyme digestion was subjected to various furnace experiments designed to assess the fouling and slagging characteristics. Results of these analyses suggest the residue to be of a low to moderate slagging and fouling type if burned by itself.     

Production of single cell protein (SCP) from food and agricultural waste by using Saccharomyces cerevisiae

Food waste is the single-largest component of the waste stream, in order to protect and safeguard the public health, useful and innovative recycling methods are investigated. The conversion of food wastes in value-added products is becoming a more economically viable and interesting practice. Food waste, collected in the distribution sector and citrus industries, was characterised for its potential as a raw material to use in fermentation processes. In this study, the production of single-cell protein (SCP) using food waste as a substrate was investigated. The purpose of this study has been to produce SCP from mixtures of food waste using Saccharomyces cerevisiae. The main fermentation test was carried out using a 25 l bioreactor. The utilisation of food waste can allow us to not only to reduce environmental pollution, but also to obtain value-added products such as protein supply for animal feed.     

纤维素燃料乙醇废液与煤的成浆性能研究

提出了一种纤维素燃料乙醇废液大规模资源化利用的新方法—将纤维素燃料乙醇废液与煤共混制备废液煤浆作燃料用。借助旋转黏度计对废液煤浆(WLCS-CEF)进行流变性测定,研究了成浆浓度、废液加入量和添加剂对煤浆流变性的影响。结果表明,废液煤浆的表观黏度随成浆浓度及废液加入量的增加而增大,添加剂的加入明显改善废液煤浆的流变特性。废液中大分子量的木质素及未水解完全的纤维素和半纤维素能起到稳定煤浆的作用,同浓度下的废液煤浆比水煤浆稳定性高,且煤浆稳定性随浓度增大而增强,合适的添加剂也能改善稳定性。当选择添加剂A,成浆浓度为62%,废液添加量为煤量的2.5%时,制得的废液煤浆比较适合气化。