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Karn S.K.,Shandong Academy of Sciences | Chakrabarti S.K.,Thapar Center for Industrial Research and Development
International Journal of Recycling of Organic Waste in Agriculture | Year: 2015

Background: Present research communicates the role of Eisenia fetida in converting pulp and paper mill sludge into valuable products by removing the high concentration of different chlorophenols and metals present in the sludge. Results: Pulp and paper mill sludge was toxic to Eisenia fetida and therefore, it was mixed with composted material in different ratio of experimental set up such as Set up: 1, (95:5), Set up: 2 (80:20) and Set up: 3 (50:50) on dry weight basis. We found very promising results by the application Eisenia fetida in the sludge. Eisenia fetida removed all the twelve different chlorophenols more than 95 % from the sludge which is declared as carcinogenic compounds by United States Environmental Protection Agency (US-EPA) in 90 days of incubation. Heavy metals concentration was decreased significantly during the incubation period whereas some metal concentration was also increased in the sludge due to mineralization. Carbon (C) and Nitrogen (N) were increased in the composted material, C:N ratio for Set 1 9:4 in Set 2 13:4 and Set 3 18:4 was observed which acts as soil conditioner. Whereas some other metals like (Ca, Mg, Na, K, Fe and Zn) was increased that are essential for the plant growth. There was great reduction in adsorbable organic halogen (AOX) 95 % and extractable organic halogen (EOX) 90 % as compare to control. Eisenia fetida also removed pentachlorophenol (PCP) from the sludge with artificially increased concentration about 100 mg/kg. Conclusions: By observing chlorophenols concentration, metals and carbon–nitrogen ratio, Eisenia fetida is acting as a potential candidate for the reclamation of industrial sludge. The result indicated that vermicomposting with Eisenia fetida is better option to manage the sludge or convert the sludge into nutrient-rich composted material in a short span of time. © 2015, The Author(s).


Chauhan V.S.,Indian Institute of Technology Roorkee | Bhardwaj N.K.,Thapar Center for Industrial Research and Development
Nordic Pulp and Paper Research Journal | Year: 2013

The inorganic fillers added to the paper interfere in the inter-fibre bonding and decrease the paper strength. They could not be added beyond a certain limit due to decreased paper strength and machine runnability. The talc filler was preflocculated using different doses (0.1 to 0.8%) of commercial amphoteric starch. The cooked amphoteric starch was added to talc slurry under controlled conditions. The preflocculated talcs were added to the bleached mixed hardwood kraft pulp to produce the laboratory handsheets targeting the varying ash content (15 to 24%). The particle size distribution, micro images and colloidal charge of the preflocculated talcs were measured and compared with the native talc. The filler retention, tensile, burst, tear, Z-direction tensile strength, bending stiffness, air permeability, scattering coefficient, opacity and brightness of sheets made using preflocculated talcs were compared to those of native talc. The particle size of preflocculated talc was increased up to 174%. Relatively higher filler retention and paper strength, and comparable opacity were obtained with amphoteric starch preflocculated talc compared to the native talc. SEM images of the sheets were also taken to understand the distribution pattern of preflocculated and native talcs within the sheet.


Karn S.K.,Thapar University | Chakrabarti S.K.,Thapar Center for Industrial Research and Development | Reddy M.S.,Thapar University
Biodegradation | Year: 2011

A pentachlorophenol (PCP) degrading bacterium was isolated and characterized from sludge of pulp and paper mill. This isolate used PCP as its sole source of carbon and energy and was capable of degrading this compound, as indicated by stoichiometric release of chloride and biomass formation. Based on morphology, biochemical tests, and 16S rRNA gene sequence analysis this strain was identified as Kocuria sp. CL2. High Performance Liquid Chromatography (HPLC) analysis revealed that this strain was able to degrade PCP up to a concentration of 600 mg/l. This is first time we are reporting the degradation of PCP by the Kocuria species. This isolate was also able to remove 58.64% of PCP from the sludge within two weeks. This study showed that the removal efficiency of PCP by CL2 was found to be very effective and can be used in degradation of PCP containing pulp paper mill waste in the environment. © 2010 Springer Science+Business Media B.V.


Kumar N.,IIT | Bhardwaj N.K.,IIT | Chakrabarti S.K.,Thapar Center for Industrial Research and Development | Kumar S.,Thapar Center for Industrial Research and Development
Powder Technology | Year: 2012

In the present study, calcium sulphate pigment has been synthesized experimentally from commercial grade calcium chloride. The effect of various factors on the particle size of calcium sulphate formed in a wet process and its potential application as pigment in coating recipe has been investigated. The operating factors investigated include concentration of calcium chloride solution, temperature, addition of different rheology modifiers and their optimization. The particle shape and size distribution of synthesized calcium sulphate pigment have been studied through image analyzer, scanning electron microscope (SEM) and particle size analyzer. Significant improvement was observed in various coated paper properties like brightness, whiteness, gloss, stiffness, surface strength and water retention properties of coating color with respect to conventional ground calcium carbonate (GCC) coating pigment. © 2011 Elsevier B.V.


Chauhan V.S.,Thapar Center for Industrial Research and Development | Chakrabarti S.K.,Thapar Center for Industrial Research and Development
Cellulose Chemistry and Technology | Year: 2012

Nanotechnology is of great importance in almost all modern day industries targeting high quality, efficiency and market potential. The large interest in the nano-scale range is due to the fact that nanomaterials can have enhanced properties, as compared to the same material with larger particle size. The modification of cellulose into different types of micro- and nano-structures has been reported in literature. In papermaking, nanotechnological advances were reported about a decade ago, though it could not be commercialized at a large scale. Nanofiber, nanofiller, nanocomposites and nanoscale chemicals to be used in pulp and paper applications are in main focus. Because of the wide abundance, renewable and environmentally benign nature, and outstanding mechanical properties of nano-based cellulosic materials, great attention has been paid to their use in pulp and paper, and other industries. There are a few challenges associated with their efficient use at a commercial scale, such as cost, lack of compatibility among materials and knowledge gap. This review of recent work discusses the manufacturing, application and properties of different nanoparticles and nano-based technological developments reported by researchers worldwide, related to cellulose and paper manufacturing.


Karn S.K.,Thapar University | Chakrabarty S.K.,Thapar Center for Industrial Research and Development | Sudhakara Reddy M.,Thapar University
International Biodeterioration and Biodegradation | Year: 2010

Pentachlorophenol (PCP) degrading Bacillus strains CL3, CL5, and CL11 were isolated from the secondary sludge of a pulp paper mill and characterized. These isolates were identified as Bacillus megaterium, Bacillus pumilus, and Bacillus thuringensis based on their 16S rRNA sequence analysis. These isolates were able to grow and utilize PCP as a carbon and energy source. HPLC analysis and stoichiometric release of chloride in the medium confirmed the degradation ability of these isolates. The removal efficiency of PCP by these bacterial isolates was highly significant and they were able to degrade more than 90% of PCP when grown at high concentration of PCP (600mgl-1). Consortia of these isolates removed 77% of PCP from the sludge. The removal efficiency of PCP by the bacterial isolate used in this study was found to be more efficient than what has been reported with other Bacillus species. These results suggest that the bacterial isolates are very effective PCP degraders and can be used in remediation of PCP-contaminated sites. © 2010 Elsevier Ltd.


Karn S.K.,Thapar University | Chakrabarty S.K.,Thapar Center for Industrial Research and Development | Reddy M.S.,Thapar University
Journal of Environmental Sciences | Year: 2010

A pentachlorophenol (PCP) mineralizing bacterium was isolated from the secondary sludge of pulp and paper mill and identifi as Pseudomonas stutzeri strain CL7. This isolate used PCP as its sole source of carbon and energy and was capable of degrading th compound as indicated by stoichiometric release of chloride and biomass formation. P. stutzeri (CL7) was able to mineralize a hi concentration of PCP (600 mg/L) than any previously reported Pseudomonad with PCP as sole carbon source. As the concentrati of PCP increased from 50 to 600 mg/L, the reduction in the cell growth was observed and the PCP degradation was more than 90 in all studied concentrations. This isolate was able to remove 66.8% of PCP from the secondary sludge of pulp and paper mill wh supplemented with 100 mg/L of PCP and grown for two weeks. This study showed that the removal efficiency of PCP by CL7 w found to be very effective and can be used in PCP remediation of pulp paper mill waste in the environment. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.


Chauhan V.S.,Indian Institute of Technology Roorkee | Bhardwaj N.K.,Indian Institute of Technology Roorkee | Chakrabarti S.K.,Thapar Center for Industrial Research and Development
Canadian Journal of Chemical Engineering | Year: 2013

Fillers are essential component of printing papers to increase the opacity, brightness, and to improve formation and printing properties. As a very little work has been reported so far on magnesium silicate (talc), the study was conducted with the filler of different particle size for papermaking. The sheets were made in the laboratory with refined mixed hardwood chemical pulp with five grades of talc, ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC) fillers with 15-24% ash level. Apparent density along with tensile, burst, tear index, Z-direction tensile strength (ZDTS) and bending stiffness index were evaluated for talc filled sheets, and compared with GCC and PCC. Physical strength properties of talc filled sheets were decreased at a faster rate on increasing filler loading in paper and decreasing the particle size of the filler. With same type of filler its particle size determines the physical properties of paper. The postulate was not found to be valid for all the three varieties of fillers viz., talc, PCC and GCC. Shape and geometry of the PCC and GCC fillers determine the individual property. © 2012 Canadian Society for Chemical Engineering.


Chauhan V.S.,Indian Institute of Technology Roorkee | Bhardwaj N.K.,Thapar Center for Industrial Research and Development
Appita Journal | Year: 2013

Loading of inorganic fillers in paper decreases the inter-fibre bonding and paper strength. To overcome the reduction in paper strength, preflocculated talc filler was investigated using different doses of commercial cationic starch, with the cooked starch being added to the talc slurry under controlled conditions. The preflocculated talc fillers were then used during papemnaking to improve the properties of filled handsheets made in laboratory from bleached mixed hardwood kraft pulp. The particle size distribution and retention of filler as well as tensile, burst, tear, Z-direction tensile strength, bending stiffness index, air permeability, scattering coefficient and opacity of paper using native and preflocculated talcs were compared. The particle size and image analysis showed that using 0.8% starch Increased the particle size of talc filler by 87%. The use of preflocculated talc resulted in relatively higher filler retention and paper strength and comparable optical properties of paper. Scanning electron micrographs indicated that the preflocculated talc particles were more effectively adhered and bonded to the fibre network in comparison to the native talc.


Singh Chauhan V.,Indian Institute of Technology Roorkee | Bhardwaj N.K.,Thapar Center for Industrial Research and Development
Appita Journal | Year: 2013

Five talc fillers of different particle size distribution (PSD) and platy shape were used in a laboratory papermaking study, along with two reference fillers viz, ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC). Sheets were prepared from all fillers using 0.5% (w/v) dosage of alkyl ketene dimer sizing chemical with the ash in paper ranging from 14 to 24%. The effect of PSD, shape and increasing filler content on sizing characteristics of paper measured by Cobb60 and contact angle was studied. The Cobb 60, values increased and contact angles decreased on decreasing particle size of talc. The worst sizing performance was observed with calcium carbonate fillers; PCC was worse than GCC. Talc provided excellent hydrophobicity in paper due to its intrinsic hydrophobic nature. Contact angles of filled sheet with talc and calcium carbonate were in the range of 96 to 120° and 28 to 109°, respectively. Talc preflocculated with starch further improved the hydrophobicity of paper.

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