Conversion of solid wastes and natural biomass for deciphering the valorization of biochar in pollution abatement: A review on the thermo-chemical processes

Removal of fluoroquinolone antibiotic and sulfonated dye by functionalized Persea americana seed powder: Appraisal on phase transfer kinetics, equilibrium, economics, and applications in rural settings

The study focuses on reactive orange 16 (RO16), a sulfonated dye, and ciprofloxacin (CiP), a fluoroquinolone antibiotic treatment from aquatic surface by adsorption. The functionalized Persea americana seed powder (PASP) was developed by acid hydrolysis technique and investigated for RO16 and CiP removal in batch scale at different concentrations for CiP and RO16, pH (2-8), contact duration and temperature (303-318K). Utilizing a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDAX), the generated native PASP were assessed for their morphological characteristics. Fourier transform infrared (FTIR) spectroscopy was applied to examine the performing characteristics of PASP. Experimental findings with four kinetic mathematical models allowed the estimation of the process involved in the biosorption. The most effective agreement was explained by the pseudo-second-order model and Sips isotherm (Cip = 34.603 mg/g and RO16 = 30.357 mg/g) at 303K temperature. For Cip Process economics of the biosorbent was done, and it was observed that it was less than the readily market-available activated carbon.

A review on carbon-based biowaste and organic polymer materials for sustainable treatment of sulfonamides from pharmaceutical wastewater

Frequent detection of sulfonamides (SAs) pharmaceuticals in wastewater has necessitated the discovery of suitable technology for their sustainable remediation. Adsorption has been widely investigated due to its effectiveness, simplicity, and availability of various adsorbent materials from natural and artificial sources. This review highlighted the potentials of carbon-based adsorbents derived from agricultural wastes such as lignocellulose, biochar, activated carbon, carbon nanotubes graphene materials as well as organic polymers such as chitosan, molecularly imprinted polymers, metal, and covalent frameworks for SAs removal from wastewater. The promising features of these materials including higher porosity, rich carbon-content, robustness, good stability as well as ease of modification have been emphasized. Thus, the materials have demonstrated excellent performance towards the SAs removal, attributed to their porous nature that provided sufficient active sites for the adsorption of SAs molecules. The modification of physico-chemical features of the materials have been discussed as efficient means for enhancing their adsorption and reusable performance. The article also proposed various interactive mechanisms for the SAs adsorption. Lastly, the prospects and challenges have been highlighted to expand the knowledge gap on the application of the materials for the sustainable removal of the SAs.

Thermo-chemical behaviour of Dunaliella salina biomass and valorising their biochar for naphthalene removal from aqueous rural environment

Thermo-chemical behavior of a microalgal biomass; Dunaliella salina was investigated through thermo-gravimetric analyses. Fully-grown D. salina biomass were subjected for biochar conversion using pyrolytic treatment at three distinct heating rates such as 2.5, 5, and 15 °C min-1. The kinetic appraisals were explained by using model-free kinetics viz., Kissinger-Akahira-Sanose, Flynn-Waal-Ozawa and Starink iso-conversional correlations with concomitant evaluation of activation energies (Ea). The Ea value is 194.2 kJ mol-1 at 90% conversion in FWO model, which is higher as compared to other two models. Moisture, volatile substances, and other biochemical components of the biomass were volatilized between 400 and 1000 K in two separate thermo-chemical breakdown regimes. Microscopic and surface characterization analyses were carried out to elucidate the elemental and morphological characteristics of the biomass and biochar. Further, the proficiency of the prepared biochar was tested for removing naphthalene from the watery media. The novelty of the present study lies in extending the applicability of biochar prepared from D. salina for the removal of a model polyaromatic hydrocarbon, naphthalene.

Application of Biomass Smoldering for Rural Building Heating in China: Strengths and Challenges

Biomass smoldering for rural building heating could be a potential choice for bioenergy utilization in China to reduce the pollution caused by agroresidues open burning and to satisfy the increased demand of rural building heating. Its strengths include low pretreatment, transportation, and storage fees of fuel; ease of operation; good fertilizer characteristics of ash; use of latent heat of water vapor; pollution reduction; reduction of pests, weeds, and plant diseases on the farm; etc. However, controls of the burn rate and the gas emission are two challenges of the application, and related solutions of these challenges are discussed.