A novel intensified approach for treating produced water from oil extraction using a multi-tube type falling-film distillation column equipped with a biphasic thermosiphon: a promising feasibility study.

This study has the novel aim of experimentally examining the efficiency of a pilot-scale treatment plant, composed of a multi-tube type falling-film distillation column equipped with a biphasic thermosiphon, for treating a real sample of high-salinity produced water (electrical conductivity of 20,700 μS cm). It investigates the influence of operational parameters, including feed temperature and steam chamber temperature of the biphasic thermosiphon, on distillate flow rate and reduction of conductivity. All experimental conditions tested achieved a reduction greater than 98% in terms of electrical conductivity.

Chitosan as a matrix of nanocomposites: A review on nanostructures, processes, properties, and applications.

Chitosan is a biopolymer that is natural, biodegradable, and relatively low price. Chitosan has been attracting interest as a matrix of nanocomposites due to new properties for various applications. This study presents a comprehensive overview of common and recent advances using chitosan as a nanocomposite matrix.

Low temperature formation of cobalt in silicon nitride toward functional nitride nanocomposites.

This work highlights the first demonstration of a low-temperature in situ formation of Co nanocrystallites embedded within an amorphous silicon nitride matrix through careful control of the chemistry behind material design using perhydropolysilazane (PHPS) as a Si3N4 precursor further coordinated with CoCl2 and ammonia as a pyrolysis atmosphere. The Co nucleation was allowed to proceed at temperatures as low as 400 °C via thermal decomposition of Co2N pre-formed in situ by the reaction of CoCl2 with the Si centers of PHPS at the early stage of pyrolysis (220-350 °C).

In-Situ Synthesis and Characterization of Nanocomposites in the Si-Ti-N and Si-Ti-C Systems.

The pyrolysis (1000 °C) of a liquid poly(vinylmethyl--methyl)silazane modified by tetrakis(dimethylamido)titanium in flowing ammonia, nitrogen and argon followed by the annealing (1000-1800 °C) of as-pyrolyzed ceramic powders have been investigated in detail. We first provide a comprehensive mechanistic study of the polymer-to-ceramic conversion based on TG experiments coupled with in-situ mass spectrometry and ex-situ solid-state NMR and FTIR spectroscopies of both the chemically modified polymer and the pyrolysis intermediates. The pyrolysis leads to X-ray amorphous materials with chemical bonding and ceramic yields controlled by the nature of the atmosphere.

Influence of dye class on the comparison of direct contact and vacuum membrane distillation applied to remediation of dyeing wastewater.

This work investigated the influence of dye class on permeate flux and color rejection by comparing direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) applied to remediation of dyeing wastewater. The same operating system at the feed side was used and the driving force of each configuration was determined. Reactive and disperse dye solutions were considered, and a commercial membrane was employed.

Valorization of royal palm tree agroindustrial waste by isolating cellulose nanocrystals.

A considerable increase in royal palm cultivation as a result of industrialization of canned heart of palm has generated large amounts of renewable lignocellulosic waste, but reuse is still rarely practiced. In this work, for the first time, cellulose nanocrystals (CNCs) were extracted from the leaf sheath discarded from the royal palm harvest. Chlorine-free purification methods were used and strong acid hydrolysis synthesis with different times and temperatures were performed.

Dissolution of adhesive resins present in plastic waste to recover polyolefin by sink-float separation processes.

This study investigated the dissolution of adhesive resins present in polyolefin films that cause plastic materials to adhere to each other. The process of dissolution was made by the use of ethyl acetate and followed by separation through the sink-float process. The objective was to separate and characterize polyolefin films from plastic solid waste derived from recycled post-consumer paper.

Dye synthetic solution treatment by direct contact membrane distillation using commercial membranes.

The reuse of treated dyeing wastewater has become a viable option to minimizing water scarcity problems and environmental impacts in the textile industry. The potentiality of commercial flat sheet membranes of polytetrafluoroethylene (PTFE) and polypropylene (PP) in direct contact membrane distillation (DCMD) for dye synthetic solution treatment has been explored in this work. DCMD is interesting for the textile industry since a recovery of heat by hot dyeing wastewater for thermal energy is possible.

Influence of different textile fibers on characterization of dyeing wastewater and final effluent.

Textile industry needs to recover and reuse its wastewater as to fulfil the demand of increasingly strict regulations. The characterization of dyeing wastewater samples according to textile fiber and final textile effluent enables the application of different treatment methods. This study aims to characterize dyeing wastewater in black color of polyamide, polyester, and viscose fibers and final textile effluent.

Direct contact membrane distillation for textile wastewater treatment: a state of the art review.

To meet surging water demands, water reuse is being sought as an alternative to traditional water resources. Direct contact membrane distillation (DCMD) has been increasingly studied in the past decade for its potential as an emerging cost effective wastewater treatment process and subsequent water reuse. This review presents a comprehensive overview of the current progress in the application of DCMD for textile wastewater treatment based on the available state of the art.

Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔCp) for prediction of retention time in gas chromatography - Part I (Theoretical).

An approach that is commonly used for calculating the retention time of a compound in GC departs from the thermodynamic properties ΔH, ΔS and ΔCp of phase change (from mobile to stationary). Such properties can be estimated by using experimental retention time data, which results in a non-linear regression problem for non-isothermal temperature programs. As shown in this work, the surface of the objective function (approximation error criterion) on the basis of thermodynamic parameters can be divided into three clearly defined regions, and solely in one of them there is a possibility for the global optimum to be found.

Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔCp) for prediction of retention time in gas chromatography - Part II (Application).

For this work, an analysis of parameter estimation for the retention factor in GC model was performed, considering two different criteria: sum of square error, and maximum error in absolute value; relevant statistics are described for each case. The main contribution of this work is the implementation of an initialization scheme (specialized) for the estimated parameters, which features fast convergence (low computational time) and is based on knowledge of the surface of the error criterion. In an application to a series of alkanes, specialized initialization resulted in significant reduction to the number of evaluations of the objective function (reducing computational time) in the parameter estimation.

Characterization of the mucilage extracted from jaracatiá (Carica quercifolia (A. St. Hil.) Hieron).

The mucilage of the jaracatiá fruit (Carica quercifolia (A. St. Hil.

Fast and accurate numerical method for predicting gas chromatography retention time.

Predictive modeling for gas chromatography compound retention depends on the retention factor (ki) and on the flow of the mobile phase. Thus, different approaches for determining an analyte ki in column chromatography have been developed. The main one is based on the thermodynamic properties of the component and on the characteristics of the stationary phase.