Batch Studies for Methylene Blue Removal and Recovery by Untreated Coffee Residues

This paper reports the practicability of using coffee residues to remove widely used basic dyes like MB （Methylene Blue） from wastewaters. The effect of different batch system parameters, namely stirring speed, pH, initial dye concentration and contact time were studied. Moreover, in continuous fixed-bed column systems, the effects of parameters such as bed-depth, flow rate and initial dye concentration were examined. The experimental batch systems data were simulated using （a） Freundlich, Langmuir and Sips isotherm models and （b） 1st order, 2nd order, and intra-particle kinetic models. The results revealed that the MB is fairly adsorbed on coffee residues. This process could be a low cost technique for the removal of basic dyes from aqueous systems.

Fixed-bed-column Studies for Methylene Blue Removal and Recovery by Untreated Coffee Residues

This paper contributes to the Industrial Ecology Concept by using a common urban solid waste, i.e., coffee residues, to clean industrial wastewaters polluted by basic dyes, e.g., Methylene Blue. For the data from the continuous fixed-bed column system, two common models, namely （a） Bohart and Adams and （b） Clark were implemented. The Bohart and Adams capacity was up to N = 46,166 mg.L-1 or q0 = 104.5 mg.g-1 for bed-depth 15 cm, initial dye concentration 800 mg.g-1 and flow rate 20 mL.min-1. The results revealed that the Methylene Blue is fairly adsorbed on coffee residues. Consequently, this process can be applied as a low cost technique for cleaning basic dyes from the aquatic environment.

Carbon Dots Derived from Coffee Residue for Sensitive and Selective Detection of Picric Acid and Iron(III)Ions

A facile method was developed to prepare carbon dots(CDs)by pyrolysis and etching of coffee residue.The as-prepared CDs show uniform spherical nanoparticles with an average size of 2.3 nm and exhibit excitation-dependent fluorescence emissions.Moreover,CDs also exhibit strong fluorescence quenching to nitro compounds and metal ions in both water and ethanol solutions,which could act as a platform for dual detection of PA(picric acid)and Fe^(3+)ions with low detection limits of 0.26 and 0.83µmol/L,respectively.This work provides a novel method for preparation of environmental-friendly fluorescent CDs and shows their potential applications in photoluminescence sensors.

Low-temperature plasma induced phosphate groups onto coffee residue-derived porous carbon for efficient U(Ⅵ) extraction

For the continuous utilization of nuclear energy and efficient control of radioactive pollution, low-cost materials with high efficient U(VI) removal are of great importance. In this study, low temperature plasma method was applied for the successful modification of Ophosphorylethanolamine(O-PEA) on the porous carbon materials. The produced materials(Cafe/O-PEA) could adsorb U(VI) efficiently with the maximum sorption capacity of 648.54mg/g at 1 hr, T=298 K, and p H=6.0, much higher than those of most carbon-based composites. U(VI) sorption was mainly controlled by strong surface complexation. From FTIR,SEM-EDS and XPS analyses, the sorption of U(VI) was related to the complexation with-NH2, phosphate and-OH groups on Cafe/O-PEA. The low temperature plasma method was an efficient, environmentally friendly and low-cost method for surface modification of materials for the effective enrichment of U(VI) from aqueous solutions.