Application of ultrafiltration-complexation process for metal removal from pulp and paper industry wastewater

In recent years, the pulp and paper industries have been trying different technologies to reduce fresh water consumption in paper mills. This has led to a fast development of new wastewater treatment technologies for industrial reuse. Lately, water-soluble polymeric ligands have shown to be powerful substances to remove trace metals from industrial wastewater through ultrafiltration (UF). In the present study, polyethyleneimine (PEI) and polyvinylalcohol (PVA) were used as water-soluble polymeric macroligands. The UF experiments were carried out in stirred dead-end cells. The membrane used was formed from polyvinilidene fluoride (PVDF). The performance of water-soluble polymeric ligands was evaluated by determining metal removal and chemical oxygen demand (COD). In general, the complexation–ultrafiltration process was efficient for metal removal from wastewater, leading to a better effluent quality when compared to ultrafiltration without any ligands addition.     

Alternative energy sources and technologies for the pulp and paper industry

Applied Biochemistry and Biotechnology - Weyerhaeuser—together with Amoco Corporation, Carolina Power and Light, and Stone and Webster Engineering Corporation—carried out a feasibility...     

Treatment of pulp and paper mill wastewaters with poly aluminium chloride and bagasse fly ash

The present study deals with the use of poly aluminium chloride (PAC) as a coagulant and bagasse fly ash (BFA), which is generated in sugar mills, as an adsorbent for the removal of chemical oxygen demand (COD) and colour of pulp and paper mill effluents. Under optimal conditions of pH 3 and initial PAC dosage of 3 g/l, about 80% COD removal and 90% colour removal were obtained. The optimal conditions for the adsorptive removal of COD and colour with BFA were pH 4 and BFA dosage of 2 g/l. Under these conditions, COD and colour removal were, respectively, 50 and 55%. Adsorptive removal of COD by BFA followed second-order kinetics. Intra-particle diffusion was found to be rate controlling. Freundlich and Langmuir adsorption isotherms were found to fit the equilibrium adsorption data with BFA. Two-stage treatment using PAC (3 g/l) as a coagulant in the first stage and BFA (2 g/l) as an adsorbent in the second stage gave the combined COD and colour removal of nearly 87 and 95%, respectively, for different effluents without any pH adjustment. Two-stage adsorptive treatment using BFA (2 g/l) in both the stages gave a combined COD and colour removal of about 70%. The sludge obtained can be dewatered by centri-clarifiers, dried, briquetted and incinerated to recover its energy content.     

Improved analysis of process liquors for the pulp and paper industry by ion chromatography

In this paper, techniques are presented to overcome interferences from caustic matrices and neighboring ions found in process solutions. Column switching and the use of low-capacity columns to characterize strongly retained analytes are described. Oxalate, sulfide, sulfite, sulfate and thiosulfate are characterized on one set of separator columns. High-capacity cation-exchange resins are shown to be an effective pre-treatment tool for neutralizing a caustic chlorine dioxide scrubbing liquor, enabling baseline resolution of chlorate.     

The use of electron beam for solution of some ecological problems in pulp and paper industry

In the report, results of research on possibility of using a beam of accelerated electrons for a decrease of exhaust in an environment of detrimental smelling nasty substances generated during sulfate cellulose-paper production are presented. The two methods of radiation usage are described: with a direct action of beam on detrimental substances containing gas or water on a so-called “tailing” of production process and at the beginning of production with influence of electron beam on wood chips before the boiling process.     

Experiences on the analysis of PCDDs and PCDFs in pulp and paper industry matrices

Summary Some remarks on the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans in pulp and paper industry matrices are presented. The way in which samples are dried and the solvent which is used for extraction can affect the results. For the separation of individual congeners, three capillary columns with different lengths and polarities have been compared. The effect of the resolution of the mass spectrometer has been tested for pulp samples.     

Calibration transfer between electronic nose systems for rapid In situ measurement of pulp and paper industry emissions

Electronic nose systems when deployed in network mesh can effectively provide a low budget and onsite solution for the industrial obnoxious gaseous measurement. For accurate and identical prediction capability by all the electronic nose systems, a reliable calibration transfer model needs to be implemented in order to overcome the inherent sensor array variability. In this work, robust regression (RR) is used for calibration transfer between two electronic nose systems using a Box–Behnken (BB) design. Out of the two electronic nose systems, one was trained using industrial gas samples by four artificial neural network models, for the measurement of obnoxious odours emitted from pulp and paper industries. The emissions constitute mainly of hydrogen sulphide (H₂S), methyl mercaptan (MM), dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) in different proportions. A Box–Behnken design consisting of 27 experiment sets based on synthetic gas combinations of H₂S, MM, DMS and DMDS, were conducted for calibration transfer between two identical electronic nose systems. Identical sensors on both the systems were mapped and the prediction models developed using ANN were then transferred to the second system using BB–RR methodology. The results showed successful transmission of prediction models developed for one system to other system, with the mean absolute error between the actual and predicted concentration of analytes in mg L⁻¹ after calibration transfer (on second system) being 0.076, 0.1801, 0.0329, 0.427 for DMS, DMDS, MM, H₂S respectively.     

Computer system for a small analytical research laboratory

A solution to three problems concerning computer use in our laboratory is described. The problems are: replacement of obsolete computer equipment, consolidation of data processing programs, and unification of the format of kinetic data from different sources. The solution involves use of a central super microcomputer with personal computers used primarily for data acquisition and temporary storage.     

A new type of a spectrometric microtitration set up

A spectrometric microtitrator was developed from a spectrometer with a microreaction chamber and a tri-colour light-emitting diode (LED) as the light source. A novel, vertical, optical geometry of the spectrometric microtitration chamber was introduced and tested. This novel geometry also required a new method for mixing the titrated solution. A laboratory-made 50 μl syringe pump was used for the addition of the titration reagent. The 10-channel module for light effects, which makes possible a low-cost hardware approach to changing the titration protocols, was used for coordinating the operation of the microtitration set up. The system, with 10 channels and a regulated speed of operation, is flexible enough to allow an operator to generate different titration protocols. The performance test showed that the speed of titration-reagent addition can be regulated in the range from 0.87 to 21.8 μl min⁻¹. The smallest achievable volume addition is equal to 35 nl. The mixing rate can be continuously regulated by an electrical pulse that initiates the mixing cycle. The quickest rate is every 1.6 s, and the slowest rate is every 4.8 s. The spectrometric microtitration set up was successfully tested for several different real-life spectrometric titrations, including an iodometric titration, a determination of CO₂ in deionised water, and EDTA titrations of copper(II) ions with no indicator. The volume of the examined solution can be as small as 220 μl. The titration-reagent consumption is usually between 10 and 35 μl. Coefficients of variation of the end point volume determination (n = 5) at different experimental conditions and different average volumes of consumed reagents (7.06, 12.17 and 22.88 μl) were 2.4, 1.3 and 1.2%, respectively. The novel geometry of the spectrometric microtitration chamber proved to be useful for real-life applications.     

Characterisation of pulp and paper mill sludge for beneficiation

Cellulose - In this study, three different pulp and paper mill sludge (PPMS) samples collected from different South African mills were chemically and physically characterised to investigate their...     

Lead removal and recovery from battery industry wastewaters by soluble starch xanthate

Treatment, removal and recovery of lead (3 mg/L) from battery industry wastewaters have been investigated utilising a chemical precipitation process with soluble starch xanthate (SX) at pH 5-6. A reactant ratio, i.e., SX/Pb(II) = 6 mol/mol, a reaction time of 15 min., the addition of 15 mg/L of a cationic polyelectrolyte and a final filtration gave residual lead concentrations in the liquid phase less than 0.2 mg/L, well below the maximum limit established by the EU Directive. Lead was extracted from the obtained sludge by oxidation with sodium hypochlorite or hydrogen peroxide solutions. The amounts of oxidant needed were quantified as 13.5 mol NaClO/mol Pb and one order of magnitude larger, for H2O2, the latter due to the competitive disproportion reaction of the oxidant. The metal extraction was quantitative using sodium hypochlorite; when hydrogen peroxide was used, the formation of insoluble PbSO4 (Anglesite) gave a 80% metal extraction. In both cases molar ratios between sulphate and lead ions in the extracted solutions were in the range 2.1-2.2, in agreement with the stoichiometries of the reactions. Lead can be quantitatively recovered from the extracted (NaClO) solutions, for reuse, after a chemical precipitation process with 1M NaOH at pH 9-9.5, in the form of hydrocerussite [Pb3(CO3)2(OH)2].     

Analysis of monosaccharides and oligosaccharides in the pulp and paper industry by use of capillary zone electrophoresis: a review

Carbohydrate analysis is an important source of the information required for understanding and control of pulp and paper processes. The behavior of cellulose and hemicelluloses in the process, carbohydrate–lignin interactions, and the enzymatic treatment of fibers are examples of situations for which reliable, fast, qualitative, and quantitative methods are required. New uses of lignocellulosic material have further increased the need for carbohydrate analysis. This review collates and summarizes the most important findings and approaches in the analysis of wood-based carbohydrates by use of capillary zone electrophoresis and provides an analysis of the effect of different conditions on the separation, showing the advantages and limitations of the methods used. It provides guidelines for achieving higher quality and improved separation efficiency in carbohydrate analysis.

A chemometric tool for computer-aided decision making in analytical laboratory management

One of the tasks of management in analytical laboratories is the scheduling of analyses and the organization of the laboratory resources with respect to the workload. By a simulation of the laboratory operations, one can describe and eventually forecast the magnitude of the sample backlog and result delays with respect to the followed strategy to schedule samples and resources. However the design and validation of a simulation model is a lengthy and expensive task, requiring the help of a specialist in the area of operations research. In this paper an expert system is described that guides the laboratory manager through the various stages of the model design. The output of the expert system is a simulation model written in program code (SIMULA) that after compilation can be used to simulate the laboratory.     

A simple and tailor‐made fabrication of porous silicon carbide from functionalized kraft pulp paper

Porous silicon carbide (SiC) materials were fabricated using the polymer‐derived ceramics method with kraft pulp papers (KPP) and a commercial polycarbosilane, the allylhydridopolycarbosilane (AHPCS), as starting materials. For this, KPP, propargylated KPP, or phosphorylated KPP were used to be impregnated by the AHPCS, with or without Karstedt catalyst. The pyrolysed materials were characterized at different stages, by using thermogravimetric analysis (TGA) coupled with mass spectrometry, X‐ray diffraction (XRD), and scanning electron microscopy (SEM). Depending on the nature of the initial template, various architectured SiC ceramics were successfully obtained with adjustable porosities. The key role of the previous functionalization of the papers was highlighted in terms of interactions at the interface between the polymer and the lignocellulosic handsheets. It led to either replica or sacrificial template methods. Thus, it was possible to tune the open porosity of the porous carbon and β‐SiC materials between 14.8% and 92.9%, with ceramic yields varying from 12% to 71%.     

Decision-making and optimization in the analytical laboratory: A survey

A survey has been made of 300 Dutch analytical laboratories to determine which factors influence their choice of apparatus and analytical methods. The extent of their knowledge of, and familiarity with modern chemometric optimization strategies was also investigated. There was a 50% response to the survey and this article reports the results obtained.     

现代分析技术在天然活性产物中的应用

综述了近年来各种现代分析技术在天然活性产物研究领域的现状与进展.