205
8.3.7 Reverse Osmosis
In reverse osmosis, cellophane-like semipermeable membrane is used to purify
water from contaminations. In reverse osmosis, the particles move across a selectively permeable membrane under the effect of osmotic gradient created across the
semipermeable membrane. The process is augmented by external pressure. When
the pressure is provided at the concentrated side, it forces the water molecules to
move to the dilute side and retain the impurities on the other side, making water
pure and contamination-free. The impurities left behind on the concentrated side are
going away with released water. The use of reverse osmosis for water purification
includes decontamination of water from electroplating industries, fisheries, wastewater containing organic impurities, industrial waste including food processing,
textile, petrochemical, paper and pulp preparation as well as municipal and radioactive wastewater. It is also reported to be used for decontamination of groundwater
and preparing pharmaceutical and reagent grade water (Chen et al. 2018).
Most of the abovementioned conventional processes are unsuitable and unsatisfactory due to the disposal of dirt, their excessive operational price, less productivity, and less effectiveness. The major drawback is that these methods are not
applicable for large number of pollutants and less efficient for the handling of small
quantity of metallic ions and problems of further treatment because of the production of toxic sludge.
8.3.8 Adsorption
Among all filtration processes, adsorption is considered the most suitable for wastewaters, not only being cost-effective but also being simple. Adsorption is the most
popular, convenient, superior, and beneficial strategy above any other processes for
the remediation of polluted industrial wastes and elimination of contamination from
water supplies. It has many advantages such as practicality, pliancy, or malleability
in design and simplicity of working or performance and producing supercilious
emission capable for reuse free from other pollutants (Fig. 8.5).
The major advantage related to adsorption is regeneration of sorbents with
appropriate desorption process, and most of such regenerations need low maintenance cost with excess efficiency and is easy to operate. It is accepted as one of the
productive, effective, labor-saving valuable, and reasonable methods. Thus, adsorption is the most promising technique that can be utilized to eliminate certain types
of pollutants by the selection of appropriate adsorbent.
Adsorption is a process that occurs when a liquid or gaseous solute accumulates
on solid or liquid phase i.e. the adsorbent, forming an atomic or a molecular filum
i.e. the adsorbate. It takes place in almost all chemical, natural, physical and biological systems. It is mostly applied for treatment of industrial waste using a variety of
8 Agricultural Waste Absorbents for Heavy Metal Removal
8.3.7 Reverse Osmosis
In reverse osmosis, cellophane-like semipermeable membrane is used to purify
water from contaminations. In reverse osmosis, the particles move across a selectively permeable membrane under the effect of osmotic gradient created across the
semipermeable membrane. The process is augmented by external pressure. When
the pressure is provided at the concentrated side, it forces the water molecules to
move to the dilute side and retain the impurities on the other side, making water
pure and contamination-free. The impurities left behind on the concentrated side are
going away with released water. The use of reverse osmosis for water purification
includes decontamination of water from electroplating industries, fisheries, wastewater containing organic impurities, industrial waste including food processing,
textile, petrochemical, paper and pulp preparation as well as municipal and radioactive wastewater. It is also reported to be used for decontamination of groundwater
and preparing pharmaceutical and reagent grade water (Chen et al. 2018).
Most of the abovementioned conventional processes are unsuitable and unsatisfactory due to the disposal of dirt, their excessive operational price, less productivity, and less effectiveness. The major drawback is that these methods are not
applicable for large number of pollutants and less efficient for the handling of small
quantity of metallic ions and problems of further treatment because of the production of toxic sludge.
8.3.8 Adsorption
Among all filtration processes, adsorption is considered the most suitable for wastewaters, not only being cost-effective but also being simple. Adsorption is the most
popular, convenient, superior, and beneficial strategy above any other processes for
the remediation of polluted industrial wastes and elimination of contamination from
water supplies. It has many advantages such as practicality, pliancy, or malleability
in design and simplicity of working or performance and producing supercilious
emission capable for reuse free from other pollutants (Fig. 8.5).
The major advantage related to adsorption is regeneration of sorbents with
appropriate desorption process, and most of such regenerations need low maintenance cost with excess efficiency and is easy to operate. It is accepted as one of the
productive, effective, labor-saving valuable, and reasonable methods. Thus, adsorption is the most promising technique that can be utilized to eliminate certain types
of pollutants by the selection of appropriate adsorbent.
Adsorption is a process that occurs when a liquid or gaseous solute accumulates
on solid or liquid phase i.e. the adsorbent, forming an atomic or a molecular filum
i.e. the adsorbate. It takes place in almost all chemical, natural, physical and biological systems. It is mostly applied for treatment of industrial waste using a variety of
8 Agricultural Waste Absorbents for Heavy Metal Removal