## 3 Polymer Nanocomposites as Adsorbent
### Polymer Nanocomposites as Adsorbent for Dye Removal
#### 3.2.1 Polymer Nanoparticle as Adsorbent for Dye Removal
The capacity of absorption for amino-coated magnetic nanoparticles was attained at 97.3 mg g\({}^{-1}\) for Congo red, and the adsorption got to approximately 80% of the equilibrium adsorption quantity in less than 4 hours. [PERSON] et al. [148] developed a novel approach to selectively remove industrial dyes from wastewaters by utilizing the adsorption technique on the account of magnetic adsorbents. The effective removal of pollutants was dependent on initial pollutants concentration, temperature, magnetite/carbon nanocomposites dose, and solution pH, which upsurges with an upsurge in carbon content. Different optimum capacities of adsorption were attained for different dyes. [PERSON] et al. synthesized and characterized magnetic (Fe\({}_{3}\)O\({}_{4}\))/activated charcoal (AC)/\(\beta\)-cyclodextrin(cm)/sodium alginate polymer composite gel beads for the adsorption of methylene blue [149]. Their results revealed that the rate of methylene blue removal was 99.53% in 90 min. The adsorbent obtained has unique features that allows a simple recovery devoid of any substantial weight loss of the adsorbent employed. This is the confirmation that sodium alginate-based material possesses excellent mechanical properties and optimum methylene blue adsorption capacity, outstanding restoration capability, and excellent separation properties. Biopolymers are considered substances that are by nature formed through living species; hence, they are known to be ecologically pleasant and viable. Chitosan and cellulose are of precise importance on account of their ample availability, simple modification, and utilization prospective. The utilizations of biopolymer-based hydrogels and nanocomposite films are effectual biosorbents for complete removal of a collection of organic and inorganic contaminants, which includes xenobiotics from wastewater [150]. They have been specifically employed for the adsorption of metal ions and dye. [PERSON] et al. [151] prepared a biopolymer chitosan-polypropylene imine as a biocompatible adsorbent for its reactive textile dyes (reactive black 5 and reactive red 198) removal potential. On account of optimum process parameters data used in the study, the performance dye removal of 97 and 99% were respectively attained for reactive black 5 and reactive red 198. As a result of high adsorption capacity of chitosan-polyppropylene imine for reactive black 5 (6250 mg g\({}^{-1}\)) and reactive red 198 (5882.35 mg g\({}^{-1}\)), biocompatibility and eco-friendly properties of chitosan-polyppropylene imine might be an appropriate adsorbent for reactive dyes removal from wastewater. [PERSON] et al. prepared and characterized a nanoscale Davankov-type hyper-crosslinked-polymer as an adsorbent of benzene-ring-containing dyes and organic pollutants [152]. The hyper-crosslinked-polymer nanoparticles post-crosslinked from a poly(DVB-co-VBC) precursor prepared for the investigation were hydrophobic and stable. The as-synthesized hyper-crosslinked-polymer nanoparticles demonstrated a swift and selective adsorption capability to benzene-ring-containing dyes owing to its excellent conjugated structure. [PERSON] et al. synthesized magnetite nanospheres via the utilization of the silvo-thermal technique followed by modification of the surface by utilizing a synthetic polymer. The adsorbent was effectively employed for removing some anionic dyes from aqueous samples [153]. [PERSON] et al. synthesized polyaniline nanoparticles for adsorption-based crystal violet removal via the ultrasonicated adsorption process [154]. The efficiency of the process was established based on the influence on certain conditions such as sonication time, temperature, dosage of adsorbent, and crystal violet concentrations. The process was validated via the estimation of various adsorption isotherms. The nanoparticles were efficient for 94.29% dye removal from wastewater. Functionalized biopolymers (such as cellulose and chitosan) have recently attracted interests as emergent substitute approaches for organic dye removal.