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Researchers around the world are in continuous endeavor to develop environment friendly tanning agent due to adverse effect of conventionally used chromium during leather tanning. Recent trend of tanning is thus heading to chrome-free and greener chemical processing options. Vegetable tanning is an exoteric leather processing technique because of their lower pollution load on the environment. Considering the inadequacy and high costing for the commercialized tannins, development of alternative tannins from locally available plants and their characterizations are important. In this research, the stem barks of Trema Orientalis (L.) were extracted at different temperatures employing water solvent with or without additives (sodium hydroxide or sodium sulphite) to attain phenolic-rich extractives. To ascertain appropriateness as a vegetable tanning agent, the obtained extracts were thereafter characterized in respect to yield, total phenolic content, tannin content and molecular structure. The extraction yield for all extracts improves and the quality remains nearly unchanged with temperature rising. The elevated concentration of chemical additives enhances the extraction yield but lessens the quality of extracts. In terms of extraction yield and the quality of extracts the best condition for extraction was discerned at 80°C with water solvent. This water extract has a decent extent of phenolic and tannin content of 266.13 mg Gallic acid equivalent/ gm of dry extract and 30.12 % respectively. The final extract exhibits excellent leather retanning tendency comparable to the commercial quebracho tannins.

In this investigation, a nondestructive technique has been developed for determining chemical composition of jute fiber by chemometric modeling with pretreated FT-NIR spectroscopic data. The chemical composition of jute fibers in wet chemical method were, 58 to 61.80 % α-cellulose, 13.0 to 21.90 % lignin, 9.89 to 16.8 % pentosan and 79.02 to 88.33 % holocellulose. FT-NIR spectral data from range 9000–4000 cm−1 of all jute samples were collected from the instrument. Spectral data of jute samples were pretreated with second order derivatives (SOD), standard normal variate (SNV) techniques and both together were used before calibration. Two chemometric calibration techniques: partial least square regression (PLSR) and artificial neural network (ANN) were assessed for predicting chemical compositions of Jute fibers. Result shows that prediction efficiency ( R 2 {\text{R}^{2}} ) of ANN varies from 72–99 % for calibration, validation and test datasets. However, by PLSR, R 2 {\text{R}^{2}} are much higher and consistent than those by earlier one. For α-cellulose, lignin, pentosan and holocellulose R 2 {\text{R}^{2}} values hover around 95–99 %. Thereby, a non-destructive, simple and cost effective novel method is being proposed to determine chemical compositions of jute with pretreated FT-NIR spectral data and chemometric calibration techniques.

Bangladesh Government is interested to produce rayon from jute fiber. But jute fiber is an expensive raw material. Jute cuttings (JC) and jute caddis (CD) are generated as wastes in the jute mill. In this investigation dissolving pulp was produced from low grade jute (LGJ), JC and CD with 90% formic acid (FA) treatment at the boiling temperature for 4 h. JC showed the highest pulp yield (62.3%) and CD showed the lowest pulp yield (58.0%). In this process 12–13% lignin and 25–27% hemicelluloses were also separated from the spent liquor, which can integrate biorefinery. FA pulps were further alkali extracted by varying amount of alkali charge at 25 and 90 °C for 120 min. Alkali extraction reduced kappa number and residual pentosan content in pulp. In the D0EpD1 bleaching sequence, brightness of LGJ and JC pulps reached to 83–86% and pulp purity to 96% with fock reactivity of 61–67%.

Banana fibre is a natural fibre with high strength, which can be blended easily with cotton fibre or synthetic fibre to produce composite material. In the fiber extraction process, a substantial amount of lignocellulosic wastes are generated, disposal of which creates problem in the adjacent area. In this paper, extracted banana fiber (EBF) and waste banana fiber (WBF) were characterized in terms of chemical and morphological properties to produce handmade paper. WBF was characterized with lower α–cellulose, lignin content and longer fiber length. Pulping of EBF and WBF was carried out with varying active alkali and cooking time at boiling temperature. Pulp yield of WBF was 35.9% after 120 min of cooking with 8% alkali charge. In the unbeaten state the degrees of drainage resistance i.e. SR values were 65 and 71 for EBF and WBF, respectively. The tensile, burst and tear indices of WBF were 23.7 N.m/g, 2.2 kPa.m2/g and 5.0 mN.m2/g, respectively; these were much lower as compared to EBF. These values however, meet the requirement for handmade paper.Bangladesh J. Sci. Ind. Res.53(2), 83-88, 2018

Chrome tanning is a versatile tanning system, but the pollution problems of chromium due to inadequacy of treatment systems and possible formation of Cr(VI), a carcinogen, have led to search for an ecofriendly and viable alternative tanning system. The present investigation focuses on the development of a novel, high performance and thermally stable aldehyde tannage system to produce chrome free leather by cross linking the NH 2 groups of collagen with glutaraldehyde (CHO-CH 2 -CH 2 -CH 2 -CHO). After as usual soaking, liming, deliming, bating and pickling operations the pickle pelts were tanned with glutaraldehyde and other syntans. This developed chrome free tanning process produce crust leathers exhibiting thermal stability >85°C and reducing the TDS value with 0% emission of Cr-salt in tannery discharge. Key words : Eco friendly tanning system, Chrome free leather, Crust leathers  doi: 10.3329/bjsir.v43i4.2246  Bangladesh J. Sci. Ind. Res. 43(4) , 553-558, 2008