196
8.3.10 Adsorbent Properties
207
8.3.11 Factors Affecting Adsorption
207
8.3.12 Various Adsorbents Used in Adsorption Processes
208
8.3.13 Low-Cost Adsorbent
214
8.4 Agricultural Wastes
217
8.4.1 Agricultural Waste as Low-Cost Adsorbents
218
8.5 Conclusion
222
References
223
Abstract Large numbers of toxic and poisonous chemicals are released in our surroundings from different industries resulting in contamination of aqueous medium,
atmosphere, and geosphere at an alarming level. Aqueous medium pollution that
results from heavy metal has come into being as a severe environmental issue. Some
poisonous metals include zinc, mercury, lead, chromium, cadmium, nickel, and
copper, which are of particular concern in curing industrial wastewater. They are
non-biodegradable in nature, make aggregate in living bodies and most of them are
cancer-causing agents. A number of extensive industrial researches have been conducted for the safe removal of pollutants and metallic elements from industrial
effluents and wastewater. There are many different ordinary treatment strategies that
have been utilized to treat these aqueous phase toxins, such as flotation, ionexchange, coagulation, reverse osmosis, electrolysis, and complexation.
The adsorption is more widely accepted, and more promising techniques can be
utilized to eliminate certain types of pollutants by selecting appropriate adsorbent.
It offers many advantages over other conventional methods and is accepted as one
of the productive, effective, labor-saving, valuable, and reasonable methods. There
are large number of adsorbents that have been used to adsorb heavy metals from
aqueous media such as activated carbon, activated alumina, clays, zeolites, polymer
clay-based nanoadsorbents, metal oxide-based nanoadsorbents, graphene, and carbon nanotubes; some other absorbents including chitosan, lignin, cellulose, starch,
and fungi have also been used for safe removal of heavy metals. Agricultural wastes
come from the growing and initially processed agricultural stuff, including organic
products, vegetables, fruits meat, and dairy items, which nowadays have been used
as economic and environment-friendly adsorbents. Agricultural wastes especially
those that contain cellulose have a high biosorption capacity. Adsorbents from plant
wastes can be used with or without modification for the reduction of a pollutant
from aqueous media. Generally, chemical modification of plant wastes enhances
their adsorption capacities as compared to unmodified. Rice husk in pristine form
and in activated rice form is utilized for chromium (VI) removal. Different kinds of
agricultural waste materials including peanut shells, soybean hulls, rice straw,
bagasse, sugarcane, and walnut shells have been applied for lead adsorption. In
some studies, rice and wheat bran were analyzed for cadmium adsorption, and
excellent results were reported. Other studies showed the application of rice husk
and rice polish in both pristine and composite forms for effective cadmium adsorption. The bark of some plants including Picea glehnii and Abies sachalinensis and
biomass of dried plants (Parthenium) were checked for cadmium removal.
Adsorption experiments performed using hazelnut shells, green shell, walnut shells,
A. Sabir et al.
8.3.10 Adsorbent Properties
207
8.3.11 Factors Affecting Adsorption
207
8.3.12 Various Adsorbents Used in Adsorption Processes
208
8.3.13 Low-Cost Adsorbent
214
8.4 Agricultural Wastes
217
8.4.1 Agricultural Waste as Low-Cost Adsorbents
218
8.5 Conclusion
222
References
223
Abstract Large numbers of toxic and poisonous chemicals are released in our surroundings from different industries resulting in contamination of aqueous medium,
atmosphere, and geosphere at an alarming level. Aqueous medium pollution that
results from heavy metal has come into being as a severe environmental issue. Some
poisonous metals include zinc, mercury, lead, chromium, cadmium, nickel, and
copper, which are of particular concern in curing industrial wastewater. They are
non-biodegradable in nature, make aggregate in living bodies and most of them are
cancer-causing agents. A number of extensive industrial researches have been conducted for the safe removal of pollutants and metallic elements from industrial
effluents and wastewater. There are many different ordinary treatment strategies that
have been utilized to treat these aqueous phase toxins, such as flotation, ionexchange, coagulation, reverse osmosis, electrolysis, and complexation.
The adsorption is more widely accepted, and more promising techniques can be
utilized to eliminate certain types of pollutants by selecting appropriate adsorbent.
It offers many advantages over other conventional methods and is accepted as one
of the productive, effective, labor-saving, valuable, and reasonable methods. There
are large number of adsorbents that have been used to adsorb heavy metals from
aqueous media such as activated carbon, activated alumina, clays, zeolites, polymer
clay-based nanoadsorbents, metal oxide-based nanoadsorbents, graphene, and carbon nanotubes; some other absorbents including chitosan, lignin, cellulose, starch,
and fungi have also been used for safe removal of heavy metals. Agricultural wastes
come from the growing and initially processed agricultural stuff, including organic
products, vegetables, fruits meat, and dairy items, which nowadays have been used
as economic and environment-friendly adsorbents. Agricultural wastes especially
those that contain cellulose have a high biosorption capacity. Adsorbents from plant
wastes can be used with or without modification for the reduction of a pollutant
from aqueous media. Generally, chemical modification of plant wastes enhances
their adsorption capacities as compared to unmodified. Rice husk in pristine form
and in activated rice form is utilized for chromium (VI) removal. Different kinds of
agricultural waste materials including peanut shells, soybean hulls, rice straw,
bagasse, sugarcane, and walnut shells have been applied for lead adsorption. In
some studies, rice and wheat bran were analyzed for cadmium adsorption, and
excellent results were reported. Other studies showed the application of rice husk
and rice polish in both pristine and composite forms for effective cadmium adsorption. The bark of some plants including Picea glehnii and Abies sachalinensis and
biomass of dried plants (Parthenium) were checked for cadmium removal.
Adsorption experiments performed using hazelnut shells, green shell, walnut shells,
A. Sabir et al.