Water contamination with nitrates is a serious problem due to the detrimental effects of nitrates on both human life and the global ecosystem; therefore, it is essential to remove nitrates using efficient methods. Accordingly, various methods have been used to treat nitrate-containing solutions, but recent studies focused on electrocoagulation (ELE) as it produces high quality water at low cost and it is environmentally friendly. However, passive layers are growing on the aluminum anodes after short time of treatment, which substantially affects the efficiency of ELE. In this investigation therefore, ultrasonic filed was used to remove these passive layers, and consequently improves the efficiency of ELE. This new method, ultrasonic-assisted ELE (U-ELE), was used to remove nitrates from water under various operational conditions. In particular, the impacts of water initial pH (WIP) (4.0-8.0), applied current densities (ACD) (6.0-9.0 mA/cm2), flow rates (FR) (60-100 ml/min), and initial nitrate concentrations (INC) (100-200 mg/L), which were optimized using the Central Composite Design (CCD). The ultrasonic irradiation time (UT) has been kept at 10 minutes for all experiments. The best possible removal of nitrate using only ELE method was about 77% at WIP of 6, UT of 10 minutes, FR of 40 ml/min, INC of 150 mg/l and ACD of 7.5mA/cm2. However, it was found that exerting ultrasonic for 10 minutes, U-ELE method, has increased nitrates removal to 87.80% under the same conditions of ELE treatment.

The technique of replacing the cement with other alternative materials focus on the production of materials with similar performance and reduced environmental impacts relative to traditional cement. The main aim of this study is to investigate the effect of replacing the cement content with high volume of GGBS and PFA on the mechanical performance of cement mortar. Three mixtures were prepared with different percentages of GGBS and PFA (40%, 60% and 80%) as replacement of cement along with other mixture that made with 100% cement as a control mixture. In order to evaluate the performance of the cement mortars, compressive strength test after 7, 14 and 28 days of curing was used. The results indicated that after 7 days of curing, the increase of GGBS and PFA contents caused a reduction in the compressive strength in comparison with the control mixture. After 28 days of curing, the results indicated that the mixture incorporated 80% GGBS and PFA has higher compressive strength relative to the control mixture. Such findings will significantly contribute in reducing the cost of the produced mortar by reducing the amount of used cement and this consequently reduce the cement demands/manufacturing. Less production of cement will reduce the CO2 emissions of the cement industry.

One of the significant sources of water pollution is construction industry as it requires considerable freshwater amounts during manufacturing of concrete, mortars and other construction materials. Vast volume of the used water is discharged back to source of freshwater as extremely polluted effluent (high level of suspended solids and pH), which is categorized as hazardous wastewaters. Therefore, environmental regulations prevent discharging these effluents before conducting adequate treatment. As a result, efficient treatment solutions for these effluents become necessary in the field of construction industry. In this context, this research aims at treating construction industry effluents using an integrated method, which involves adsorption (AD) and electrochemical (EL) techniques, to treat effluents of concentration sites. Turbidity and chemical oxygen demand (COD) were selected as pollutants models due to their wide occurrence in this type of effluents. 200 mg of activated carbon (AC) and four aluminum electrodes were utilized to construct the adsorption and electrochemical units, respectively. Aluminum and AC were used here as they are economically efficient, safe, and have a proven efficiency in waters/wastewaters treatment. The influences of initial pH, retention time (RT) and electrolyzing time (ET) on the removal of COD and turbidity using the new method (AD-EL method) were examined. The results demonstrated the AD-EL decreased COD and turbidity by about 72% and 85%, respectively. The perfect conditions to reach this removal levels were pH, RT and ET of 6, 30 minutes and 20 minutes, respectively.

Occurrence of heavy metals in freshwater sources is a grave concern due to their severe impacts on public health and aquatic life. Cadmium (Cd2+) is one of the most dangerous heavy metals, and can cause serious diseases even at low concentrations. Hence, a wide range of treatment technologies exist, such as nanofiltration and biological reactors. In this context, the present investigation aims at the development of a new adsorption medium, made from chicken bones coated with iron (Fe) and magnesium (Mg) hydroxides, to remove cadmium from water. This novel chicken bone functional substance was manufactured by applying layered double hydroxides (LDH) into the chicken bones. Initially, the new adsorption medium was characterized using Fourier-transform infrared spectroscopy (FTIR technology), then it was applied to remove cadmium from water under different conditions, including pH of water (3–7.5), agitation speed (50–200 rpm), adsorbent dose (1–20 g per 100 mL), and contact time (30–120 min). Additionally, the reaction kinetics were studied using a pseudo-first order kinetic model. The results obtained from the present study proved that the new adsorption medium removed 97% of cadmium after 120 min at an agitation speed of 150 rpm, pH of 5, and adsorption dose of 10 g per 100 mL. The results also showed that the new adsorption medium contains a significant number of functional groups, including hydroxyl groups. According to the outcomes of the kinetic study, the mechanism of removing metal is attributed to surface precipitation, ion exchange, complexation, hydrogen binding between pollutants, and the LDH-chicken bone substance.

Various experimental studies have highlighted the negative consequences of Portland cement on health and the environment, such as toxic emissions and alkaline sewage. The development of environmentally acceptable substitutes for cement is thus one of the objectives of current investigations. The proposed environmental alternatives to cement, nevertheless, might have detrimental impacts on the concrete’s characteristics. This investigation intends to study the suitability as alternatives to cement in cement mortar, using industrial wastes like silica fume and cement kiln dust. As a replacement for cement, the cement mortars developed in this research continue from 0% to 60% silica fume and cement kiln dust. Ultrasonic pulse velocity tests at 1 to 4 weeks of age were conducted on hardened specimens. The findings showed that a low reduction in the pulse velocity resulted from high proportions of silica fume and cement kiln dust replacements, whereas an improvement in the characteristics of the mortars with low replacement ratios. Using low kiln dust and silica fume of 20 to 40%, the durability of mortars may increase.