Search results for "isotherm"

Influence of torrefaction pretreatment on the pyrolysis of Eucalyptus clone: A study on kinetics, reaction mechanism and heat flow

2016

Abstract The adverse nature of biomass requires specific pretreatment processes to better utilize it in bioenergy applications, and torrefaction is one of the most recognized thermal pretreatment methods. In this regard, we studied the effect of torrefaction pretreatment on kinetics, reaction mechanism and heat flow during the pyrolysis of biomass by making a comparative analysis between the pyrolysis of dried and torrefied Eucalyptus wood. Torrefied biomass was produced at three temperatures, namely 250, 275 and 300 °C. Pyrolysis was performed at 700 °C. The char yield during pyrolysis increased from 22.39 percent to 36.34 percent when the torrefaction temperature was increased from 250 to…

High-affinity and selective detection of pyrophosphate in water by a resorcinarene salt receptor

2017

N-Alkyl ammonium resorcinarenes selectively bind pyrophosphate in pure water with an exceptionally high binding constant of up to 1.60 × 107 M–1, three orders of magnitude higher than ATP.

Adsorption of anionic dyes onto natural, thermally and chemically modified smectite clays

2014

Abstract The aim of this study was to determine the adsorption capacity of the smectite clays (from the overburden of the lignite deposit in Belchatow) for two anionic dyes, i.e. Reactive Blue 81 (RB-81) and Direct Blue 74 (DB-74). Additionally, the influence of the thermal and chemical (acid and alkali) clay modifications on the amount of bonded dyes was investigated. The adsorption capacity of the clay (natural and modified) was different for studied dyes and depended on the initial concentration and modification type. All the modified clays adsorbed the dyes at pH>pHPZC as the negatively charged surfaces of their particles (in accordance with the formula: AOH ↔ AO- + H+) prevented the…

Equilibrium and studies on sorption of heavy metals from solutions by algae

2013

Removal of ammonium ions from aqueous solutions using alkali-activated analcime as sorbent

2023

Five alkali-activated analcime (ANA) sorbents (ANA-MK 1, ANA 2, ANA 3, ANA-MK 4, and ANA-MK 5) were developed for ammonium (NH4+) ion removal. Acid treatment and calcination were used as pre-treatments for analcime, and metakaolin (MK) was used as a blending agent in three sorbents. Sorption experiments were performed to evaluate the effects of sorbent dosage (1–20 g L−1), initial NH4+ ion concentration (5–1000 g L−1), and contact time (1 min–24 h). ANA-MK 1, ANA 2, and ANA-MK 4 were the most efficient sorbents for NH4+ ion removal, with a maximum experimental sorption uptake of 29.79, 26.00, and 22.24 mg g−1, respectively. ANA 3 and ANA-MK 5 demonstrated…

Surface Nanophysics: Macro-, Meso-, Micro- and Nano-approaches

2017

The surface factor is very important for manipulating objects at a nanoscale. Thermodynamic behaviour is observed from the classical point of view, and conditional division into macro-, meso-, micro- and nano-approaches is presented. Processes of physical and chemical adsorption on the surface are presented from the energy and structure aspects. The occurrence of electronic states of the surface is presented from the classical point of view in comparison with molecular electronic states. One of the most important non-invasive optical methods to investigate nanoparticles is the surface plasmon resonance (SPR), which is quite useful for practical detection of nanoparticles in the surrounding …

Dry cherry tomato: innovation from studies on isotherms

2014

The drying of vegetables is a very ancient practice for food preservation still in use nowadays. Tomatoes cut into two parts, added with salt and dried are an important element of the food tradition in south of Italy. The tomato’s drying in Sicily is still carried out with a sun-drying process, with an empiric method. The final product obtained has a high quality which it is not homogeneous. In addition to dried products, the market offer even semidry products, to limit the loss of the nutritional characteristics of the dried product. The semidry product is a special category of dehydrated products that have a residual moisture content about 30%; for this reason, nutritional product charact…

Sorption of Acid Green 16 from Aqueous Solution onto Low-moor Peat and Smectite Clay Co-occurring in Lignite of Belchatow Mine Field

2015

Celem badań było wyznaczenie pojemności sorpcyjnej iłu smektytowego i torfu niskiego towarzyszących pokładom złóż węgli brunatnych w stosunku do barwnika Acid Green 16 (AG–16) oraz określenie mechanizmu jego wiązania. Wyniki wskazały, że badany torf niski był skutecznym sorbentem barwnika AG-16 w całym zakresie stężeń początkowych (1–1000 mg/dm3), natomiast ił smektytowy – jedynie z zakresie stężeń wysokich (> 250 mg/dm3). W wyniku aktywacji termicznej iłu nastąpił wzrost jego pojemności sorpcyjnej w stosunku do badanego barwnika. Proces sorpcji barwnika przebiegał przy ujemnie naładowanej powierzchni sorbentów i wskazywał, że jednym z mechanizmów wiązania barwnika AG–16 były oddziaływania …