Benzene removal by nano magnetic particles under continuous condition from aqueous solutions

Benzene removal evaluated using Fe304 nano continuous condition. A 44 initial benzene concentration, from aqueous solutions was magnetic particles （NM） in factorial design including NM dose, contact time and pH was investigated in 16 experiments （Taguchi OA design）. The results indicated that all factors were significant and the optimum condition was： pH 8, NM dose of 2000 mg.L-1, benzene concentrations of 100 mg.L-1 and contact time of 14min. The maximum benzene uptake and distribution ratio in the optimum situation were 49.4mg.g-1 and 38.4L.g-1, respectively. The nano particles were shown to capture 98.7% of the benzene in optimum batch condition and 94.5% in continuous condition. The isotherm data proved that the Bmnauer-Emmett-Teller model fit more closely and produced an isotherm constant （b） less than one, indicating favorable adsorption. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature, and thereby, NM can be employed repeatedly in water and wastewater management.     

Removing ammonia from air with a constant pH,slightly acidic water spray wet scrubber using recycled scrubbing solution

Slightly acidic solutions are a practical means of removing ammonia from air Scrubbed NH₃ accumulates in solution as NH₄⁺ and should be an excellent fertilizer Increased air velocity decreased NH₃ removal and increased NH₄⁺ collection Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this study was to determine if a spray scrubber with slightly acidic and higher pH scrubbing solution (pH from 2 to 8) could effectively remove NH₃ from NH₃ laden air (such as animal building exhaust air), and also collect this valuable resource for later use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH₃/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8 while maintaining constant air velocity at 1.3 m·s⁻¹. Next, air velocity was increased (2 and 3 m·s⁻¹) while solution pH remained constant at pH6. At 1.3 m·s⁻¹, NH₃ removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH₃ molecules. The NH₃ removed from the air was held in solution as NH₄⁺ and accumulates over time so the solution should be an excellent fertilizer.     

Health,safety, and environmental risk assessment of steel production complex in central Iran using TOPSIS

This research was carried out with the aim of presenting an environmental management plan for steel production complex (SPC) in central Iran. Following precise identification of the plant activities as well as the study area, possible sources of environmental pollution and adverse impacts on the air quality, water, soil, biological environment, socioeconomic and cultural environment, and health and safety of the employees were determined considering the work processes of the steel complex. Afterwards, noise, wastewater, and air pollution sources were measured. Subsequently, factors polluting the steel complex were identified by TOPSIS and then prioritized using Excel Software. Based on the obtained results, the operation of the furnaces in hot rolling process with the score 1, effluent derived from hot rolling process with the score 0.565, nonprincipal disposal and dumping of waste at the plant enclosure with the score 0.335, walking beam process with the score 1.483 respectively allocated themselves the highest priority in terms of air, water, soil and noise pollution. In terms of habitats, land cover and socioeconomic and cultural environment, closeness to the forest area and the existence of four groups of wildlife with the score 1.106 and proximity of villages and residential areas to the plant with the score 3.771 respectively enjoyed the highest priorities while impressibility and occupational accidents with the score 2.725 and cutting and welding operations with score 2.134 had the highest priority among health and safety criteria. Finally, strategies for the control of pollution sources were identified and Training, Monitoring and environmental management plan of the SPC was prepared.     

The trend analysis of neurological disorders as major causes of death and disability according to human development, 1990-2019

Environmental Science and Pollution Research - This study aims to assess the trends in the incidence rate of neurological disorders in developed and developing countries worldwide during...