Reviews on the Applicability of Construction and Demolition Waste as Low-Cost Adsorbents to Remove-Heavy Metals in Wastewater

Abstract

Removal of heavy metals from wastewater is of special concern due to the persistence of heavy metals in the environment. The industrial discharge of heavy metals adversely affects soil and water resources, aquatic organisms, and ecosystem integrity. In addition, high concentrations of heavy metals are detected in solid waste landfill leachate in many developing countries due to non-segregated waste dumping. At present, various kinds of adsorbents such as activated carbon, biomass resources, geomaterials, and industrial waste products are used to treat heavy metal-contaminated water. However, the use of construction and demolition waste (CDW) and its recycled materials to treat heavy metal-contaminated water has not been fully examined. Because the generation of CDW is increasing due to rapid urbanization and a high demand for construction, the wise use of CDW and its recycled materials is necessary. This paper reviews journal articles published from 2004 to 2016 that studied the applicability of low-cost CDW adsorbents to remove heavy metals from wastewater. In particular, it summarizes results on using CDW and recycled materials such as cement, concrete, and brick compared to those from various other adsorbents such as biosorbents, geomaterials, and their industrial products. The potential applicability of CDW and its recycled materials as heavy-metal adsorbents was examined based on a comparison table listing material properties, test conditions, and measured adsorption properties.

Interactions of Cd2+, Co2+ and MoO42− Ions with Crushed Concrete Fines

“…In light of the failure to effectively recycle or reutilise the vast quantities of concrete-based C&D waste, further research into the potential use of the cement-rich fine fraction as a sorbent for aqueous heavy metal contaminants has been suggested [7,11]. Accordingly, the present study was carried out to investigate the interactions of aqueous Cd 2+ , Co 2+ and MoO4 2− ions with crushed concrete fines.…”

“…Concrete is a composite comprising a hydrated cement matrix embedded with 'aggregates' of sand, gravel and crushed rock. The mechanical crushing, sieving and sorting of concrete-based demolition waste, for the recovery and reuse of the aggregates, produces a large volume of fine (<5 mm), low-density, cement-rich material for which further market development is required [7,10,11]. In this respect, a number of recent studies has been carried out that seek to exploit the porous, absorbent and alkaline nature of the cement-rich fine material in the treatment of contaminated water [1,3,5,6,10,[12][13][14][15][16][17][18][19][20][21][22][23] and marine sediment [24][25][26].…”

Steel Slag and Autoclaved Aerated Concrete Grains as Low-Cost Adsorbents to Remove Cd2+ and Pb2+ in Wastewater: Effects of Mixing Proportions of Grains and Liquid-to-Solid Ratio

“…Many adsorption experiments have been performed to examine their adsorption capacities and characteristics [47]. However, among these low-cost adsorbents, IBPs and CDW are still marginalized in adsorption studies as well as industrial applications, although those materials have the same potential as other low-cost adsorbents to adsorb heavy metals from wastewater [36][37][38][39][48][49][50]. Therefore, more studies on the effective use of IBPs and CDW are required.…”

“…Until now, many studies have investigated the applicability of IBPs and other types of low-cost adsorbents for heavy metal treatment processes, but most of the studies mainly target the treatment of heavy metals at low concentrations (typically, heavy metal concentrations <200 mg/L) [21,[57][58][59]. Furthermore, most of these studies examined the adsorption capacities of target adsorbents in single and/or binary-metal solutions at a constant liquid-to-solid (L/S) ratio [50]. Because actual industrial wastewater might be contaminated by multi-species heavy metals like Pb 2+ , Cd 2+ , Ni 2+ , Cu 2+ , and Zn 2+ , further studies are needed to examine the simultaneous removal of heavy metals fully considering the co-existence of competitive metals in wastewater [19,60].…”

A Modified Preparation of Cellulosic‐Absorbent Resin for Cu2+ Removal under Microwave Irradiation

“…ere are various conventional technologies [1][2][3][4][5][6][7][8][9][10] to remove heavy metal ions from wastewater, such as coagulation, oxidation/filtration, chemical precipitation, reverse osmosis, absorption, electrochemistry, and ion exchange. However, there are some problems about these technologies, such as secondpollution, high-cost, and inconvenient process.…”