Emerging usage of plant-based coagulants for water and wastewater treatment

Heavy metals released from industrial activities pose a significant threat to the environment and public health due to their reported toxicity even at trace levels. Although there are several available methods to treat or remove heavy metals from water and wastewater, the research focuses on development of technological solutions which sound environmental friendly and economically feasible, able to reduce the costs and maximize the efficiency. In this framework, the biosorption process, which uses cheap and non-pollutant materials, may be considered as an alternative, viable and promising, technology for heavy metal and metalloid ions sequestration and ultimately removal technology in the waste water treatment. However, there is as yet little data on full-scale applications for the design and testing of adsorption units using single biosorbents and their combinations to sequester heavy metal ions from multi-metal systems. Immediate research and development is hence earnestly required in this specific direction to further make progress this blooming technology and widen its scope of application to real situations needing heavy metal pollution remediation. This review provides a comprehensive appraisal of the equilibrium modeling of a number of biosorption processes as well as the structural, chemical and morphological modifications and activation of biosorbents. Further the relative merits of the methods used to recover sequestered heavy metal ions and regenerate biosorbents through desorption routes and their future applications are discussed.

Biomass-derived biosorbents for metal ions sequestration: Adsorbent modification and activation methods and adsorbent regeneration

Adsorption of cadmium (II) ions from aqueous solution by a new low-cost adsorbent—Bamboo charcoal

Assessing of lead(III) capturing from contaminated wastewater using ligand doped conjugate adsorbent

Agricultural solid wastes either in natural or in modified forms have been successfully used for decades as non-conventional cost-effective adsorbents for removing metal ions and dyes from their aqueous phase and have been recognized as a sustainable solution for wastewater treatment. Therefore, this review article provides extensive literature information about heavy metals and dyes, their classifications and toxicity, various treatment methods with emphasis on adsorption characteristics by numerous agricultural solid wastes, or agricultural solid waste-derived adsorbents under various physicochemical process conditions. This review article not only provided an up-to-date information on the application of sustainable low-cost alternative adsorbents such as agricultural solid wastes, agricultural by-products, and biomass-based cost-effective activated carbon and various other natural materials in the batch adsorptive removal of heavy metal and dye from aqueous phase but also presented a comprehensive compilation of adsorptive pollutant removal information based on various reported continuous column operation studies which is one of the new aspect to this review article. The effectiveness of various batch and column operational process parameters on mechanistic adsorptive removal of both heavy metals and dyes by various agricultural solid waste-based adsorbents has been critically discussed here. Batch and column adsorption mechanism, batch kinetics, column dynamic modeling, and adsorptive behavior of adsorbents under various process parameters have also been critically analyzed and compared. Finally, literature information on recovery and regeneration through desorption techniques and cost comparison of various agricultural solid waste adsorbents with commercial activated carbons have also been reported here. Conclusions have been drawn from the literature reviewed, and few suggestions for future research direction are proposed.

A Review on Heavy Metal Ions and Dye Adsorption from Water by Agricultural Solid Waste Adsorbents

Lead(II) adsorption from aqueous solutions by raw and activated charcoals of Melocanna baccifera Roxburgh (bamboo)--a comparative study.

Biosorption of lead from aqueous solution by seed powder of Strychnos potatorum L.

Removal of Pb(II) from aqueous solution by seed powder of Prosopis juliflora DC.

Random amplified polymorphic DNA (RAPD) markers were used to assess genetic diversity in Oroxylum indicum (L.) Vent (Bignoniaceae) a vulnerable medicinal plant collected from eight locations in Andhra Pradesh, India. High level of genetic similarity was observed in the collected accessions. Forty random primers, each with 10 bases generated a total of 188 polymorphic bands out of the 387 total bands, that is, polymorphism of 49.61% was observed. Overall genetic similarity based on 40 random primers was 87%. Cluster analysis based on Dice coefficient showed two major groups. The results show that the genetic diversity of this species is low, possibly depicting a difficulty in adapting to environmental variations. This distributive pattern of genetic variation of O. indicum accessions provides important baseline data for conservation and collection strategies for this species. The collected accessions were introduced to University of Hyderabad field gene bank along with other redlisted plants of Deccan ecoregion.

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K. Jayaram

Papers

Lead(II) adsorption from aqueous solutions by raw and activated charcoals of Melocanna baccifera Roxburgh (bamboo)--a comparative study.

Biosorption of lead from aqueous solution by seed powder of Strychnos potatorum L.

Removal of Pb(II) from aqueous solution by seed powder of Prosopis juliflora DC.

Genetic diversity in Oroxylum indicum (L.) Vent. (Bignoniaceae), a vulnerable medicinal plant by random amplified polymorphic DNA marker

A combination of five mechanisms confers a high tolerance for aluminum to a wild species of Poaceae, Andropogon virginicus L.