Читать книгу Biosorption for Wastewater Contaminants - Группа авторов - Страница 33

Solid wastes derived from flora and fauna are plentiful, low‐cost, renewable resources. They're made in vast quantities every year, and disposing of them is usually a problem. An important area of research is to find meaningful uses for these materials. They can be used to minimize waste and create cost‐effective products (Kulkarni, 2014).

Plants disposed of as agricultural waste and food industry waste can be used as biosorbents. This is a method of repurposing and recycling discarded materials, so using plant materials has no significant cost (Ali Redha, 2020). Plant‐derived wastes are predominantly made up of cellulose, with structural components such as lignin, proteins, hemicellulose, carbohydrates, lipids, and starch (Rajapaksha et al., 2015). Plant biosorbents can absorb water because of the presence of carboxylic and phenolic functional groups in the cellulosic matrix and components linked with cellulose, such as hemicellulose and lignin (Abdi and Kazemi, 2015). Based on cation exchange between binding sites and metal ions, the metal ions bind with functional groups, resulting in biosorption and, therefore, the removal of the metal ions from media (Abdi and Kazemi, 2015). Table 2.5 lists the various plants employed as biosorbents.

Table 2.4 Biosorption of heavy metals by different yeasts.

Yeast biomass(biosorbent)	Metal ions(biosorbate)	References
Candida utilis	Chromium	(Anaemene, 2012)
Saccharomyces cerevisiae	Cadmium	(Das et al., 2008)
Saccharomyces cerevisiae	Cobalt	(Arakaki et al., 2011)
Candida pelliculosa	Copper	(Apinthanapong and Phensaijai, 2009)
Mucor rouxii	Lead	(Muraleedharan et al., 1991)
Saccharomyces cerevisiae	Mercury	(Anaemene, 2012)
Saccharomyces cerevisiae	Nickel	(Siñeriz et al., 2009)
Thiobacillusthiooxidans	Zinc	(Nagashetti et al., 2013)

Table 2.5 Biosorption of heavy metals by different plant materials.

Plant waste	Metal	Adsorption capacity	Reference
Wheat bran	Mercury	82%	(Farajzadeh and Monji, 2004)
Black gram husk	Lead	93%	(Saeed et al., 2005)
Rice bran	Cadmium	80%	(Montanher et al., 2005)
Baggase	Zinc	90–95%	(Mohan and Singh, 2002)
Activated carbon of peanut shells	Nickel	75%	(Wilson et al., 2006)
Barley straw	Copper	80%	(Pehlivan et al., 2012)
Coconut shell fibers	Chromium	80%	(Mohan et al., 2006)

Animal waste products are dumped as solid waste in the environment without being processed or composted or simply washed into water canals, posing a health risk to humans and other living species. The chance to use animal waste for a useful purpose is lost if they are discarded without preparation. Some research has looked into using these animal waste products as a viable adsorbent to adsorb heavy metals from effluent because they are inexpensive and conveniently accessible. Heavy metal adsorption has been researched using animal manure as an adsorbent. Animal bones, pretreated fish bones, crab shells, pretreated arca shells, pretreated crab and arca shells, eggshells, Muscadomestica, and so on are a few other examples (Srivastava et al., 2016). Table 2.6 summarizes the results of the adsorption analysis performed on animal byproducts.

Table 2.6 Biosorption of heavy metals by different animal wastes.

Animal waste	Metal	Adsorption capacity	Reference
Pretreated fish bones	Copper	150.7 mg/g.	(Kizilkaya et al., 2010)
Dried animal bones	Zinc	0.1764 mmol/g.	(Banat et al., 2002)
Crab shell	Cobalt	322.6 mg/g	(Vijayaraghavan et al., 2006)
Pretreated arca shell biomass	Lead	18.33 mg/g	(Dahiya et al., 2008)
Animal bone	Nickel	7.22 mg/g	(Al‐Asheh et al., 1999)

These adsorbents could offer significant advantages compared to currently available economically priced activated carbons and help with waste reduction. Furthermore, research is required to adapt the simulation methodology to larger manufacturing facilities rather than small experimental applications.