A Study on Cement Made by Partially Replacing Cement Raw Materials with Municipal Solid Waste Ash
The use of Municipal Solid Waste incinerator bottom ash (MSWI) and Calcium Carbide Waste (CCW) as a part of cement raw material was investigated. The purpose was not only to dispose of the wastes, but also to alleviate some environmental problems, by reducing resources usage, CO 2 emissions and energy consumption in cement manufacturing. The replacement of MSWI and CCW in raw meal was 5 and 10 percent. Chemical composition and general characteristics, as well as setting times and compressive strength, of the MSWI cements and CCW cements were tested and compared with conventional cement. The chemical compositions of MSWI cements and CCW cements were similar to the control cement, except that the SiO 2 component in MSWI cements was higher than that in control cement but the CaO component was lower. Setting times of cement pastes were slightly different when MSWI and CCW were used as raw materials in cement. The longer setting times of these cement pastes than those of control cement is due to lower C 3 S and higher C 2 S levels than in CC. Compressive strength of CCW cement mortars was closed to that of the CC cement, whereas compressive strength of mortar produced from MSWI cements was rather smaller than the control cement mortar, especially at higher MSWI percentags.
Environmental impacts of the use of bottom ashes from municipal solid waste incineration: A review
Abstract This paper presents a literature review concerning the performance from an environmental viewpoint of construction related products made with municipal solid waste incinerator bottom ash. It starts with an initial assessment of the bottom ash, and how it performs when used as aggregate substitute in cement-based products, as cement constituent and as raw feed in cement production. Evaluation of the material’s environmental performance when used as aggregate replacement in unbound and cement-bound base and subbase layers for road pavement construction, as well as in asphalt concrete layers, is also undertaken. This paper also appraises the behaviour of ceramic-based products, including glass, glass-ceramics, and general ceramics. As a result of the high quantities of potentially leachable contaminants inherent to the bottom ash, the environmental assessment carried out throughout this paper is mostly based on the materials’ leaching behaviour, but also based on life cycle assessments and gas emission analyses. The results of several leaching trials, conducted according to various specifications, were reviewed and paralleled with corresponding regulations, with the objective of establishing the products’ viability from an environmental point of view.
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions, the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed a good agreement with the data obtained by atomic emission spectrometry.