Adsorbent Scots Pine Sawdust Biology Essay

Scots pine P. Slyvestris L. is a cone-bearing tree from the Pinaceae household. The Scots pine trees are among the most commercially of import tree species in the universe. While its chief usage is as a Christmas tree, it yields deal valued for their lumber and wood mush. Enormous measures of pine sawdust are produced as by?products from lumber and wood mush industry.

Pine sawdust suggests a wide possible application to adsorbent production. The cell wall of pine sawdust consists of chiefly celluloses, hemicelluloses and lignin. The cellulose content consists of legion hydroxyl groups ( OH? ) which facilitates cationic dye removal alternatively of anionic dye remotion. Hemi?cellulose contains non merely hydroxyl groups but besides carboxylic groups ( H+ ) , adhering active sites for anionic dye. Lignin is built up with polyphenlic groups ( i.e an aromatic ring with a three?carbon side chain. ) . By and large, soft wood ( 25?35 % ) contains more lignin than difficult wood ?18?25 % ( Batzias and Sidiras,2007b ) . Tannin, a soluble complex polyhydric phenol, is besides present in pine sawdust. The elaborate chemical composing of Scots pine were reported by Sidiras et Al. ( 2011 ) and SjO§strO§m ( 1993 ) , as presented in Table 2.12.

Table 2.12: Chemical composing of Scot pine sawdust

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Component

Percentage, %

Cellulose measured as glucan ( 52.5 % XRD degree crystallinity )

40.1

Hemicellulose

28.5

Mannan

16

Xylan

8.9

Arabian

3.6

Acid indissoluble lignin

27.7

Ash

0.2

Extractives and acid soluble constituents ( e.g. acid soluble constituents )

3.5

The intrinsic composing, inexpensiveness and handiness of pine sawdust do it a good favoured low cost adsorbent. Different signifiers of pine sawdusts and cones have been antecedently used as adsorbent for the remotion of dyes and heavy metals, as shown in Table 2.13 and 2.14 severally.

Adsorbent

Pollutant

Performance

Untreated P. Slyvestris L sawdust

Lead and Vanadium

Contact Time? 160 min

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Freundlich parametric quantity presented unfavorable strength for sorption of V.

Maximum removal per centum:

Lead: 99 % at pH4

Volt: 95 % at pH4

( Kaczala et al.,2009 )

Untreated pine sawdust

Metal complex dye:

Acid Blue 256

Acid Yellow 132

Contact Time? 120 min

Adsorption Kinetics? Pseudo 2nd order and Elovich equation

Adsorption Isotherm? Langmuir

Maximal surface assimilation capacity:

Acid Blue 256: 280.3 milligram dye per g of pine sawdust

Acid Yellow 256: 280.3 milligram dye per g of pine sawdust

( E?zacar and Sengil,2005 )

Table 2.13: Surveies on pine sawdusts as an adsorbent

Adsorbent

Pollutant

Performance

H2SO4 modified Aleppo pine sawdust

Phosphate ions

Contact Time? 40 min

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Freundlich

The low value of activated energy of surface assimilation, 3.088 KJ mol?1, indicates that the phosphate ions are easy adsorbed on the sawdust.

( Benyoucef and Amrani, 2011 )

Untreated Pinus Sylestris L. fillings

Cr6+

Contact Time? 4 hours

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Langmuir and D-R isotherm

The Cr6+ remotion increased from 34.8 % to 69.41 % as the adsorptive dose increased from 3.0 to 8.0 g/L, while the consumption of Cr6+ decreased from 6.09 mg/g to 4.78 mg/g as the biosorbent dose increased from 3.0 to 8.0 g/L, when the intial Cr6+ concentration was 50 mg/L.

( Mudhoo and Seenauth, 2011 )

Tartaric acid modified ruddy pine sawdust

Cr6+

Contact Time? 120 min

Adsorption isotherm? Freundlich

Maximal surface assimilation observed at pH 3.0 and the surface assimilation ranges from 8.3 to 22.6 mg/g.

( Gode et al.,2008 )

Adsorbent

Pollutant

Performance

Untreated Pinus halepensis sawdust

Basic Methylene Blue

Cr6+

Contact Time? 10?20 min

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Freundlich

Favorable pH at 9. An adsorptive dosage of 10g/L was optimum for about complete Cd remotion within 30 min from a 5mg/L Cd solution. For all contact times, an addition in cadmium concentration resulted in lessening in the per centum Cd remotion ( 100-87 % ) , and an addition in surface assimilation capacity ( 0.11-5.36 mg/g ) .

( Semerjian,2010 )

Auto hydrolysis by the organic acids produced by the Scot pine sawdust itself

Basic dyes, methylene blue, bismarck brown and acridine orange.

In the instance of MB, the Freundlich ‘s surface assimilation capacity KF increased from 5.60 to 15.7 ( mg g?1 ) ( L mg?1 ) 1/n, the sum of dye adsorbed when impregnation is attained ( Langmuir constant qm ) increased from 38.7 to 88.0 milligram g?1, and the Bohart?Adams surface assimilation capacity coefficient N increased from 8046 to 14157 milligram L?1, bespeaking the extent that the badness of the autohydrolysis intervention enhanced the surface assimilation behavior of the stuff.

( Sidiras et al.,2011 )

Table 2.14: Surveies on pine cones as an adsorbent

Adsorbent

Pollutant

Performance

Raw pine and HCl acid treated pine cone pulverization

Anionic dye Congo

Contact Time? 100 min

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Freundlich

Maximal surface assimilation of 32.65 mg/g occurred at pH 3.55 at an initial dye concentration of 20 ppm by natural cone whereas with acid treated pine, the maximal surface assimilation of 40.19 mg/g ( Dawood and Sen,2012 ) .

Potassium hydrated oxide treated pine cone pulverization

Cu ( II ) and Pb ( II )

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Langmuir

A maximal consumption of 26.32 mg/g was obtained with Cu ( II ) and 32.26 mg/g with Pb ( II ) ( Ofomaja et al.,2010 ) .

Chemically activated pine cone by NaOH, KOH, CaOH2

Cu2+

Based intervention favoured the formation of new pores preponderantly in the order:

Raw sawdust & A ; lt ; CaOH2 & A ; lt ; KOH & A ; lt ; NaOH

( Ofomaja and Naidoo,2011 )

Cone biomass

of Pinus

sylvestris L.

Copper ( II ) and zinc ( II )

Adsorption Kinetics? Pseudo 2nd order

Adsorption Isotherm? Freundlich and Langmuir

The maximal biosorption efficiency of P. sylvestris was 67 % and 30 % for Cu ( II ) and Zn ( II ) , severally ( Ucun et al. , 2009 ) .

Surveies show that treated pine sawdust has better surface assimilation capacity that untreated one. Most of the research done to day of the month has focused on the usage of chemically treated?pine sawdust for heavy metal consumption. Very few surveies have been carried out on the consequence of chemically -treated pine sawdust on dye remotion, particularly on reactive anionic dye.

Chemical intervention enhances the surface assimilation capacity of adsorbents by supplying a higher figure of active binding sites, bettering its ion?exchange belongingss and taking to the formation of new functional groups that favour anions uptake. The most common modifying agents used can be classified as mineral organic acids ( HCl, H2SO4 ) , basal solutions ( NaOH, Na2CO3 ) , organic salts ( NaCl, MgCl2 ) and organic compounds ( Formaldehyde, methyl alcohol ) . In this survey, the consequence of organic acid in the signifier of H2SO4 and basal solution in the signifier of NaOH was investigated. The pine sawdust will be subjected to a pre?boiling intervention before any chemical pre?treatment.

Pre?Boiling Treatment

Pine sawdust contains water?soluble compounds like tannic acid which liberate a brown coloring material. Pre?boiling enables the remotion of this brown coloring material which may interfere with the analysis of RB 221 dye. During the boiling procedure, the surface country of the scot pine is increased, thereby emancipating more active binding sites ( Mudhoo and Seenauth, 2011 ) . The functional groups present in the Scot pine will besides open and polymerize, heightening its surface assimilation ability.

Sulphuric Acid Pre?Treatment

Sulphuric acid is a more efficient organic acid compared to hydrochloric acid as it provides a higher sum of H+ ions. These H+ ions provide a net positive surface to the sawdust, thereby supplying more chemically active sites for dye binding ( Tumlos et al. , 2011 ) . Raw sawdust is typified by a extremely orientated construction in the signifier of fibrils filled with stuff, confabulating an anisotropic character to the sawdust ( Singh et al. , 2011 ) . This symmetry is eliminated by intervention with sulfuric acid. Sulphuric acid is selective in its effects ( Singh et al. , 2011 ) . First, it cleans the fibrils and enhances its porousness, thereby extinguishing sawdust anisotropy and go forthing empty channels. Then, it reacts with the sawdust constituents, thereby continuing a honeycomb construction ( Alvarez et al. , 2004 ; Camacho et al. , 1996 ) . The set of chemical reactions with the sawdust constituents is as follows:

Water?Soluble Glucose

Cellulose

Hemi?Cellulose

Xylose

Degradation Merchandises

Lignin

Not Hydrolysed – Unaffected by mild H2SO4

Figure 2.6: Set of chemical reactions during H2SO4 alteration in sawdust

Batzias and Sidiras ( 2007 B ) investigated the consequence of H2SO4 pre?treatment on beech sawdust. It was noted that the hemi?cellulose content, ab initio 27.3 % w/w, decreased to 0.8 % after 4 H of H2SO4 intervention. The hydrolysis of hemi?cellulose consequences in the ‘opening ‘ of the construction of the lignocellulosic matrix ( Sidiras and Koukios, 1989 ; Sidiras, 1998 ) . However, the cellulose and lignin content remained practically unchanged. An addition in the BET surface country of the sawdust, from 2 to 6 m2/g, was besides noted ( Batzias and Sidiras,2007b ) .

Sodium Hydroxide Pre?Treatment

Sodium hydrated oxide is more efficient than Sodium carbonate. This is due to higher figure of Na+ ions in 1 g of NaOH compared to 1 g of Na2CO3. Sodium hydrated oxide is a good reagent for saponification, i.e the transition of methyl esters, which are major constituent of cellulose, hemicelluloses and lignin to carboxylate, ligands and intoxicant as shown in the equation below:

( Beginning: Wan Ngah and Hanafiah, 2008 )

On a whole, NaOH improves mechanical and chemical belongingss of sawdust such as structural lastingness, responsiveness and natural ion?exchange capacity ( Chakraborty et al. , 2011 ) .Such alkalic intervention induced the puffiness of the lingo?cellulosic stuffs which leads to an addition in internal surface country, mean pore volume and pore diameter. It was noted by SA‡iban et Al. ( 2006 ) that the surface country and mean pore diameter of poplar tree sawdust increased approximately 1.5?2 times after NaOH alteration. This intervention besides leads to a lessening in the grade of polymerization, a lessening in crystallinity, separation of structural linkages between lignin and saccharides and break of the lignin construction. NaOH treated sawdust besides shows good settling belongings, doing it easy to filtrate or divide the adsorbent from the solution ( Wan Ngah and Hanafiah, 2008 ) .

Table 2.15 shows a sum-up of different surface assimilation surveies carried on pre-boiled, H2SO4 and NaOH treated sawdust.

Table 2.15: Performance of Pre-boiled, H2SO4, NaOH and treated sawdust.

Treatment

Wood

Pollutants

Optical density, mg/g

x

Hi!
I'm Ruth!

Would you like to get a custom essay? How about receiving a customized one?

Check it out