Pre- and post-pyrolysis effects on iron impregnation of ultrasound pre-treated softwood biochar for potential catalysis applications

Slow pyrolysis is widely used to convert biomass into useable form of energy. Ultrasound pre-treatment assisted pyrolysis is a recently emerging methodology to improve the physicochemical properties of products derived. Biochar, the solid residues obtained from pyrolysis, is getting considerable attention because of its good physicochemical properties. Various modification techniques have been implemented on biochars to enhance their properties. Ultrasonic pre-treated wood biochar has showcased efficient surface and adsorption properties. Iron impregnated biochar is interesting as it has potentially proved the efficiency as an efficient low-cost catalyst. In this study, by combining the advantages of ultrasonic pre-treatment and iron impregnation, we have synthesized a series of Fe-impregnated biochar from softwood chips. Pre- and post-pyrolysis methods using a lab-scale pyrolyser had been implemented to compare the pyrolysis product yields and degree of impregnation. Biochars derived from ultrasound pre-treated woodchips by post pyrolysis demonstrated better impregnation of Fe ions on surface with better distribution of pyrolysis products such as biochar and biogas. The surface functionality of all ultrasound pre-treated biochars remained the same. However, post-pyrolysed samples at high frequency ultrasound pre-treatment showed better thermal stability. The chemical characteristics of these modified biochars are interesting and can indeed be used as a cost-effective replacement for various catalytic applications.

Effect of Physical and Chemical Activation on Arsenic Sorption Separation by Grape Seeds-Derived Biochar

The utilization of carbon-rich pyrolysis materials in the separation processes of metalloids plays a crucial role in analytes pre-concentration techniques and opens a burning issue in new sorbents development. This study characterized the effect of physical and chemical activation with subsequent iron impregnation of grape seed-derived biochar on sorption removal of As from model aqueous solutions. Sorbents that were produced in slow pyrolysis process at 600 °C were characterized by SEM, elemental, and specific surface area analysis. Sorption separation of As by the studied materials was characterized as on contact time and an initial concentration dependent process reaching sorption equilibrium in 1440 min. Air activated biochar (A1GSBC) showed about 7.7 times and HNO3 activated biochar (A2GSBC) about 6.8 times higher values of Qmax as compared to control (GSBC). A1GSBC and A2GSBC can be easily and effectively regenerated by alkali agent in several cycles. All of these results showed the practical use of the activation process to produce effective sorption materials with increased surface area and improved sorption potential for anionic forms separation from liquid wastes.

The Full Extent

Almost any single one of the techniques employed in the investigations suffices to reveal the elaborateness of the deception which was perpetrated at Piltdown. The anatomical examination, the tests for fluorine and nitrogen bear particularly good witness to this; even the radio-activity results taken alone, led the physicists to remark on the ‘great range of activity shown by specimens from this one little site’; ‘it is difficult to avoid the conclusion that the different bones in the Piltdown assemblage have had very different geological and chemical histories’. We have merely to take account of the stained condition of the whole assemblage, to realize the thoroughness of the fraud. From the Vandyke brown colour of the unnaturally abraded canine we infer with certainty that it was deliberately ‘planted’. The superficiality of the iron impregnation, combined with the chromium, tells as much as regards the orang jaw. And it is this iron-staining which finally shows that the rest, human and animal, was without doubt, all ‘planted’. The iron-staining has two peculiar features. It seems probable that ferric ammonium sulphate (iron alum) was the salt employed. This salt is slightly acid. The peculiarity of this salt (and, indeed, of any acid sulphate) is that in bone which contains little organic matter such as the cranium of Piltdown I, or Piltdown II, the beaver bones and hippo teeth, it brings about a detectable change in the crystal structure of the bone. In the apatite in which the calcium of the bone is held, the phosphate is replaced by sulphate to form gypsum. This change is quite unnatural, for neither gypsum nor sufficient sulphate occur in the gravels at Piltdown to bring it about. So the iron-sulphate-staining is an integral part of the forger’s necessary technique. He also used chromium compounds to aid the iron-staining probably because he thought it would assist the production of iron oxide. Chromium compounds are oxidizing. The basic strategy underlying the Piltdown series of forgeries now seems reasonably clear. Two main elements in the plan taken together explain nearly all the features of the affair quite satisfactorily.

Preparation of Activated Carbon from Lapsi Seed Stone and its Application for the Removal of Arsenic from Water

In this paper, Guaranteed Services Token (GuST) protocol for integrated Adsorption of arsenic by activated carbon prepared from locally available Lapsi seed stone is presented. Activated carbon has been prepared by carbonization of Lapsi seed stone (chorespondias axillaris, Roxb) in a nitrogen atmosphere at 400°C. Chemical activation using a 1:1 ratio of Lapsi seed stone powder and zinc chloride followed by iron impregnation greatly enhanced the arsenic adsorption capacity for adsorption of arsenic from ground water. Activated carbon of dose 2g/L decreased the concentration of arsenic in water from 800 ppb to below the interim guide line value of 50 ppb of arsenic in drinking water of Nepal. The iodine number of raw carbon is quite low but chemical activation using 1:1 Lapsi seed powder and zinc chloride at 400°C increased the iodine number to 791mg/g. Iron impregnated activated carbon prepared from locally available Lapsi seed stones can be used in community level at point- of- use for treatment of arsenic contaminated ground water.Key words: activated carbon; Arsenic removal; Adsorption; Chorespondias axillaris; Iron impregnated carbonDOI: http://dx.doi.org/10.3126/jie.v8i1-2.5113Journal of the Institute of Engineering Vol. 8, No. 1&2, 2010/2011Page: 211-218Uploaded Date: 20 July, 2011