353
Conventional methods for heavy metal elimination from water stream are precipitation, advance oxidation, ion- exchange process, membrane separation, biosorption,
etc. Among these processes, biosorption is an effective process due to its economical operation, abundant availability of biomaterials, easy operating process, and
high competence of metal eradication. This section focuses on the effect of toxic
metals, the metal removal options available in literature, and the adsorbents which
are utilized for metal removal.
14.2 Sources of Heavy Metals and Their Hazardous Effect
Heavy metals such as Cr, Pb, Cu, Co, Hg, Cd, As, Fe, Se, V, Ni, and Zn have great
hazardous effects on living beings. The metals are mainly discharged from various
industries like mining, fertilizer, pesticides, and chemical manufacturing which are
responsible directly or indirectly for the contamination of surface and groundwater.
Major sources of discharging various hazardous heavy metals and their health
effects are presented in Table 14.2.
14.3 Conventional Methods for Hazardous Heavy
Metal Eradication
14.3.1 Chemical Precipitation
It has simple operating procedure, higher efficiency, and low operating cost, so it is
considered as the good process for metal removal (Ku and Jung 2001). The coagulant is added to the metal-contaminated wastewater, and then the metal gets precipitated which is separated by using sedimentation or filtration process. Coagulants
have long-chained polymers consisting of cationic and anionic charge which react
with metal ion and bind the molecules together. There are mainly two types of
chemical precipitation processes where one is hydroxide precipitation and the other
is sulfide precipitation. Various chemical precipitation processes found in the literature are illustrated in Table 14.3.
14.3.2 Ion-Exchange Process
An ion-exchange process is an important treatment process which has great removal
capacity, and it is used commercially for large-scale treatment processes (Kang
et al. 2004). Several types of resins are utilized in treatment processes. In metal
14 Biomass-Based Absorbents for Heavy Metal Removal
Conventional methods for heavy metal elimination from water stream are precipitation, advance oxidation, ion- exchange process, membrane separation, biosorption,
etc. Among these processes, biosorption is an effective process due to its economical operation, abundant availability of biomaterials, easy operating process, and
high competence of metal eradication. This section focuses on the effect of toxic
metals, the metal removal options available in literature, and the adsorbents which
are utilized for metal removal.
14.2 Sources of Heavy Metals and Their Hazardous Effect
Heavy metals such as Cr, Pb, Cu, Co, Hg, Cd, As, Fe, Se, V, Ni, and Zn have great
hazardous effects on living beings. The metals are mainly discharged from various
industries like mining, fertilizer, pesticides, and chemical manufacturing which are
responsible directly or indirectly for the contamination of surface and groundwater.
Major sources of discharging various hazardous heavy metals and their health
effects are presented in Table 14.2.
14.3 Conventional Methods for Hazardous Heavy
Metal Eradication
14.3.1 Chemical Precipitation
It has simple operating procedure, higher efficiency, and low operating cost, so it is
considered as the good process for metal removal (Ku and Jung 2001). The coagulant is added to the metal-contaminated wastewater, and then the metal gets precipitated which is separated by using sedimentation or filtration process. Coagulants
have long-chained polymers consisting of cationic and anionic charge which react
with metal ion and bind the molecules together. There are mainly two types of
chemical precipitation processes where one is hydroxide precipitation and the other
is sulfide precipitation. Various chemical precipitation processes found in the literature are illustrated in Table 14.3.
14.3.2 Ion-Exchange Process
An ion-exchange process is an important treatment process which has great removal
capacity, and it is used commercially for large-scale treatment processes (Kang
et al. 2004). Several types of resins are utilized in treatment processes. In metal
14 Biomass-Based Absorbents for Heavy Metal Removal