Silver nanoparticles treated activated carbon as effective sorbent for the removal of acid Red 1 dye from aqueous media: Kinetic and equilibrium studies

429-436Silver nanoparticles (AgNPLs) impregnated onto activated carbon (AC) as an effective solid adsorbent has been used for the uptake of acid red 1 (AR) from aqueous solution. In acid medium at pH ≤ 4.0, the removal of AR is found favourable than at pH ≥ 4.0. The data approve well with Fruendlich model and pseudo second-order kinetic. Adsorption capacity calculated from Langmuir is 107.5 mg/g. Thermodynamic activation parameters suggest endothermic and spontaneous process. Silver nanoparticles enhanced uptake of AR by AC. The liquid-film and intra-particle diffusion types examined the adsorption mechanism. Removal of AR from AC-AgNPLs surface carried out to illustrate the recapture of the adsorbent and adsorbate for the economic value of the remediation system. The solid phase extractor is excellent recovered for six consecutive sorption–adsorption round elucidate its rise reused

Silver nanoparticles treated activated carbon as effective sorbent for the removal of acid Red 1 dye from aqueous media: Kinetic and equilibrium studies

Silver nanoparticles (AgNPLs) impregnated onto activated carbon (AC) as an effective solid adsorbent has been used for the uptake of acid red 1 (AR) from aqueous solution. In acid medium at pH ≤ 4.0, the removal of AR is found favourable than at pH ≥ 4.0. The data approve well with Fruendlich model and pseudo second-order kinetic. Adsorption capacity calculated from Langmuir is 107.5 mg/g. Thermodynamic activation parameters suggest endothermic and spontaneous process. Silver nanoparticles enhanced uptake of AR by AC. The liquid-film and intra-particle diffusion types examined the adsorption mechanism. Removal of AR from AC-AgNPLs surface carried out to illustrate the recapture of the adsorbent and adsorbate for the economic value of the remediation system. The solid phase extractor is excellent recovered for six consecutive sorption–adsorption round elucidate its rise reused

A case study for developing eco-efficient street lighting system in Saudi Arabia

It is now well-known phenomenon that energy efficiency has highest short-term pay out period to decrease overall energy consumption. The replacement of conventional lighting technology with innovative lighting solutions can save up to 40 % of lighting energy. The ecological evaluation of street light provision system in King Abdulaziz University (KAU), Jeddah is carried out using Sustainable Process Index (SPI) methodology. This study is carried out selecting three commonly used street illuminating devices i.e. High Pressure Sodium (HPS) lamps, Compact Fluorescent (CF) lamp and Light Emitting Diode (LED). The results show that energy consumption can be decreased by a factor of 1 to 4 by replacing HPS lamp with high efficiency LED lamp. Similarly, environmental assessment results reveal that ecological footprint as well as carbon footprint caused by lighting service can also be lowered by replacing HPS and CF lamps with LED lamps

Phosphate Removal and Recovery Using Iron Nanoparticles and Iron Cross-Linked Biopolymer

Nanoscale zero-valent iron (NZVI) particles and iron cross-linked alginate (FCA) beads were successfully used for the first time for phosphate removal and recovery. NZVI was successfully used for phosphate removal and recovery. Batch studies indicated a removal of ~96 to 100% phosphate in 30 min (1, 5, and 10 mg PO43--P/L with 400 mg NZVI/L). Phosphate removal efficiency by NZVI was 13.9 times higher compared to Microscale ZVI (MZVI) particles. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters. The presence of sulfate, nitrate, and humic substances and the change in ionic strength in the water marginally affected phosphate removal by NZVI. A maximum phosphate recovery of ~78% was achieved in 30 min at pH 12. Novel iron cross-linked alginate (FCA) beads were synthesized, characterized and used for phosphate removal. The beads removed up to 37-100% phosphate from aqueous solution in 24 h. Freundlich isotherm was found to most closely fit with experimental data and the maximum adsorption capacity was found to be 14.77 mg/g of dry beads. The presence of chloride, bicarbonate, sulfate, nitrate, and natural organic matters in aqueous solution did not interfere in phosphate removal by FCA beads. The phosphate removal efficacy FCA beads was not affected due to change in pH (4-9). Nanosacle zero-valent iron (NZVI) and iron cross-linked alginate beads were also tested for phosphate removal using actual wastewater treatment plant effluent and animal feedlot runoff. The FCA beads could remove ~63% and ~77% phosphate from wastewater and feedlot runoff in 15 min, respectively. Bioavailability of phosphate was examined using algae and higher plants. Phosphate and iron bioavailability of the NZVI sorbed phosphate was examined by supplying spent particles (NZVI with sorbed phosphate) to Tyee Spinach (Spinacia oleracea) and algae (Selenastrum capricornutum). Results revealed that the phosphate was bioavailable for both the algae and spinach. Also, presence of the nanoparticles enhanced the algae growth and plant growth and increases in biomass and plant length were observed. Iron (from spent NZVI) was found to be bioavailable for spinach

Nanoparticle-Sorbed Phosphate: Iron and Phosphate Bioavailability Studies with Spinacia oleracea and Selenastrum capricornutum

In this study, nanoscale zero-valent iron (NZVI) particles have been used for phosphate recovery from aqueous solutions. The bioavailability of the phosphate sorbed onto NZVI particles was determined using spinach (Spinacia oleracea) and algae (Selenastrum capricornutum) grown in hydroponic solutions. Simultaneous bioavailability of iron (from NZVI) was also determined. Spent NZVI particles (after phosphate adsorption) were added to the algae and spinach growth media as the only source of phosphate and iron. Phosphate sorbed by NZVI was bioavailable to both algae and spinach. The concentration of algae increased by 6.7 times when the only source of phosphate was spent NZVI as compared to algae grown in standard all nutrient media (including phosphate). Again, removing phosphate from the growth media decreased the algae concentration ∼3 fold when compared to algae grown in all-nutrient media. In the spinach study, plant biomass increased in the presence of spent NZVI (where nanoparticles were the only source of phosphate) by 2.2–4 times more than the plant treated with the all-nutrient solution. Results also indicated 21, 11, and 7 times more iron content in the roots, leaves, and stems of the spinach treated with spent NZVI, respectively, as compared to the controls

Pyrolytic liquid fuel: a source of renewable electricity generation in Makkah

Millions of Muslims from all over the world visit the Holy Cities of Saudi Arabia: Makkah and Madinah every year to worship in form of Pilgrimage (Hajj) and Umrah. The rapid growth in local population, urbanization, and living standards in Makkah city along with continually increasing number of visitors result in huge municipal solid waste generation every year. Most of this waste is disposed to landfills or dumpsites without material or energy recovery, thus posing substantial environmental and health risks. The municipal plastic waste is the second largest waste stream (up to 23% of total municipal waste) that is comprised of plastic bottles, water cups, food plates, and shopping bags. The sustainable disposal of plastic waste is challenging task due to its clogging effects, very slow biodegradation rates, and presence of toxic additives and dyes. Pyrolysis is one of the promising waste-to-energy technology for converting municipal plastic waste into energy (liquid fuel) and value-added products like char. The produced liquid fuel has the potential to be used in several energy-related applications such as electricity generation, transportation fuel, and heating purposes. It has been estimated that the plastic waste in Makkah city in 2016 can produce around 87.91 MW of electricity. This is projected to increase up to around 172.80 MW of electricity by 2040. A global warming potential of 199.7 thousand Mt.CO2 eq. will be achieved with savings of 7.9 thousand tons emission of CH4, if pyrolysis technology is developed in Makkah city. Furthermore, a total savings of 297.52 million SAR from landfill diversion, electricity generation, and carbon credits would be possible to achieve in 2016 from pyrolysis. These economic benefits will increase every year and will reach up to 584.83 million SAR in 2040

Promoting Nanotechnology among Middle School Students: Development and Implementation of Lesson Plans

Abstract Hands-on experience on nanotechnology was offered to the seventh grade students at West Fargo STEM Middle School using grade appropriate teaching modules developed in collaboration with subject teachers from West Fargo Public Schools. The content of the modules complemented course contents in science and mathematics in the seventh grade class. Eighty six students from the school participated in this year long program. Pre-and post-surveys were conducted and additional information on students' perspective on various issues were collected to evaluate the effectiveness of the program. The results indicate that hands-on activities help in stimulating students' interest in technologies. The authors believe that these programs can be emulated by others in promoting engineering education and research. The pre-and post-survey data also indicate that the students do not have enough information to decide their career paths and there is a need for additional outreach activities on science, technology, engineering, and mathematics (STEM) education and careers among the students