In this study, leaf and frond date palm waste as feedstock was used to derive biochars. The effects of pyrolysis temperatures on their physical and chemical properties, and their capacity to remove copper, iron, nickel and zinc from single and multi-metal solutions at various pH values were investigated. Analytical and spectroscopic techniques such as scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, X-ray diffraction, carbon, hydrogen, nitrogen, sulfur elemental analysis, Brunauer Emmett Teller analysis were conducted for characterization. The pore volume, surface area, pH, and total carbon content of date palm leaf and frond biochar increased while functional groups and hydrogen, nitrogen and oxygen content of biochar decreased with increasing pyrolysis temperature compared to feedstock. The removal efficiencies and sorption capacity for single and mixed metal ions were found between 98 and close to 100% and 2.4 and 3.0 mg g− 1 by leaf and frond biochar samples at pH > 6, respectively. Biochar obtained from different feedstock at different pyrolysis temperature did not show any statistically significant improvements on the removal of single or mixed metals from aqueous solutions. The date palm leaf or frond biochar obtained at low pyrolysis temperature is as effective to remove metals as the ones obtained at high pyrolysis temperatures. Therefore, to consume less energy to produce biochar at lower temperature which exhibits same effective removal efficiency will be a win-win solution in terms of sustainability and economy. As a result, date palm waste biochar can be effectively used to remove metals in water and wastewater.

No abstract

Construction is among the leading industries/activities contributing the largest carbon footprint. This review paper aims to promote awareness of the sources of carbon footprint in the construction industry, from design to operation and management during manufacturing, transportation, construction, operations, maintenance and management, and end-of-life deconstruction phases. In addition, it summarizes the latest studies on carbon footprint reduction strategies in different phases of construction by the use of alternative additives in building materials, improvements in design, recycling construction waste, promoting the utility of alternative water resources, and increasing efficiencies of water technologies and other building systems. It was reported that the application of alternative additives/materials or techniques/systems can reduce up to 90% of CO2 emissions at different stages in the construction and building operations. Therefore, this review can be beneficial at the stage of conceptualization, design, and construction to assist clients and stakeholders in selecting materials and systems; consequently, it promotes consciousness of the environmental impacts of fabrication, transportation, and operation.

No abstract

Locally available and low cost granular gravel as an adsorbent material was employed to determine its capacity to remove metal cations Cu(II), Fe(II), Ni(II), and Zn(II) from single metal solution and landfill leachate samples. Adsorption kinetics and mechanism under different parameters including dosage, time, and pH were studied. It was found that the experimental results fitted to the Freundlich model suggesting an adsorption process on a multilayer heterogeneous surface for both single metal solution and landfill leachate samples. The adsorption of metal cations followed second-order kinetics occurring in a single step on the surface of gravel. The order of removal efficiency of metals was found to be Cu(II)(98%) > Fe(II)(87.5%) > Zn(II)(76.05%) > Ni(II)(36.38%) in single metal solution and Cu(II)(98.3%) > Fe(II)(83%) > Zn(II)(48%) > Ni(II)(27.32%) in landfill leachate sample at pH 7. The regeneration efficiency of the metals adsorbed on the gravel resulted in the order of Fe(II)(99.54%) > Cu(II)(99%) > Ni(II)(49.46%) > Zn (II)(2.25%).