Reinforcement of thermoplastic rejects in the production of manhole covers

Thermoplastic rejects are un-recyclable plastics that are either incinerated causing harmful emissions into the air or land-filled. A common problem associated with manhole covers is the theft of the cover made out of cast iron and then selling it on the black market leaving a large empty hole in the road causing many potential safety and health hazards. This paper investigates the reinforcement of un-recyclable thermoplastic rejects to be used in the application of a manhole cover. Foundry sand and steel were used with the thermoplastic rejects as reinforcement of the material. Foundry sand is a hazardous waste that may cause many potential health hazards. It was shown that with 10% foundry sand, 90% thermoplastic rejects, and a steel mesh of diameter size 12 mm reinforcement, the manhole cover could withstand an average load of 112 kN. This value exceeds Grades A, AA, AAA, and B of acclaimed standards BS EN 124 for manhole covers, which ultimately indicates that the manhole cover may be used in pedestrian precincts and areas with occasional vehicular access. This composite material is produced out of waste materials (foundry sand and un-recyclable thermoplastic rejects) thus not utilizing or depleting the earth's natural resources, and eliminating the safety hazards, health hazards, and pollution associated with these waste materials. Not only is this product a benefit to the environment, but also inexpensive due to the fact that the materials are un-recyclable waste materials, and thus do not attain any value or cost.     

Releases of phosphate fertilizer industry in the surrounding environment: Investigation on heavy metals and polomum-210 in soil

Distribution of Cu,Zn,Pb,Cr,Ni,Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean Sea has been determined.Nineteen sampling sites were distributed around the industrial zone on a surface area of about 100,000 m2.Atomic absorption spectroscopy and Alpha spectroscopy were used to quantify the heavy elements and polonium-210,respectively.Investigation on a particle scale was conducted by TEM and SEM coupled to EDX and X-ray cartography to determine the nature of heavy elements carders and their distribution.Heavy elements were mainly concentrated inside the particle size fraction ＜ 50μm.Their levels decreased with distance increasing from the industry.According to the reference soil,enrichment factors were about 10,15,32 and 100 times for Zn,Pb,Cu,and Cr,respectively inside the particle size fraction ＜ 50 μm on the closest sites to the industry.The main contaminant sources were transport and storage of row materials and the free release of phosphogypsum waste.Heavy elements were entrapped inside agglomerates of sulfates,phosphates and iron oxihydroxides in a diffused shape.Polonium-210 with an enrichment factor of about 56,showed the same behavior of the spatial distribution of the trace elements.     

Environmentally sustainable applications of agro-based spent mushroom substrate (SMS): an overview

Agricultural wastes such as lignocellulosic residues are renewable resources can be used for mushroom cultivation. Spent mushroom substrate (SMS) is defined as leftover of biomass generated by commercial mushroom industries after harvesting period of mushroom. Mushroom cultivation using agricultural wastes promises a good quality of SMS for producing beneficial products such as animal feeding and fertilizers. Based on the published papers, the major applications of SMS are animal feedstock, fertilizer, energy production and wastewater treatment. For instance, some species of mushroom such as Pleurotus spp. and Agaricus bisporus are suitable for applications of ruminant feedstock and fertilizers. This paper reviews the recent studies about the beneficial usage of SMS which is considered as a waste since 2013.     

Synthesis of Polyurethane and Characterization of its Composites Based on Alfa Cellulose Fibers

Polyurethane (PU) based on polycaprolactone (PCL) and 4,4′ diphenyl methylene diisocyanate (MDI) was synthesized using a two-step method. The PU obtained was then blended with various amounts of cellulose extracted from alfa stems to prepare composite materials. The influence of cellulose on the thermal and mechanical properties of different composites was demonstrated by means of several characterization techniques such as Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM)…     

内质网应激在PFOS致大鼠肝损伤中的作用

通过全氟辛烷磺酸(PFOS)28 d大鼠经口染毒评价PFOS肝损伤效应,探讨内质网应激在PFOS毒效应中的作用。Wistar大鼠随机分组,分别以0 mg·kg^-1、5 mg·kg^-1和10 mg·kg^-1 PFOS灌胃染毒28 d。HE染色观察大鼠肝脏形态改变。ELISA法测定各组丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)、碱性磷酸酶(ALP)和淀粉酶(AMY)含量变化。紫外分光光度法测定肝组织匀浆中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性变化。RT-PCR检测肝脏内质网应激标志蛋白表达水平。结果表明,PFOS造成大鼠体重降低、肝重增高(P<0.05),组织切片显示肝细胞出现脂质沉积。PFOS不同剂量组大鼠ALT随暴露浓度增加,分别为(50.96±10.02) U·L^-1、(71.73±11.55) U·L^-1,显著高于对照组(P<0.05),AST、ALP含量与对照组相比显著上升(P<0.05),高剂量组AMY水平为(833.46±63.05) U·L^-1,与对照组相比显著降低(P<0.05)。GSH-Px和SOD水平随PFOS浓度增加出现了显著降低(P<0.05),而MDA水平显著升高(P<0.05)。内质网应激标志蛋白表达均较对照组显著上升(P<0.05)。以上结果说明PFOS可导致大鼠肝细胞损伤,其机制可能与内质网应激调控有关。     

Biosorption of Direct Yellow 12 from aqueous solution using green alga Ulva lactuca

The potential of commonly available green alga Ulva lactuca was investigated as viable biomaterials for removal of synthetic azo dye (Direct Yellow 12, DY-12) from aqueous solution. The results obtained from the batch experiments revealed that the ability of the U. lactuca to remove DY-12 from its aqueous solution was dependent on the dye concentration, pH, and algal biomass but less dependent on the particle size of the U. lactuca. The equilibrium conditions and kinetics of adsorption were investigated, and the adsorption kinetic was consistent with the pseudo-second-order model (R ²=1). The adsorption isotherm followed only the Freundlich model with a correlation coefficient R ²=0.99. This study demonstrated that the U. lactuca could be used as an effective biosorbent for the removal of DY-12 from its aqueous solution.     

Pb in medicinal plants from Jordan

This is the first report on Pb in medicinal herbs from Jordan. Medicinal herbs may present a health risk due to the presence of toxic metals. Seventy-nine dry medicinal plant samples were collected from herbalist shops in Jordan. The plants were digested with acids and analyzed for total Pb concentration using atomic absorption spectrometry. Mean Pb concentration was 15.9 μg/g on a dry weight basis. Our results show that Pb concentrations in Jordan medicinal plants are higher than published data in other countries. The highest level of 33.4 μg Pb/g was determined in Inula viscosa, and the lowest level of 3.0 μg Pb/g was found in Nigella sativa. Calculated daily intakes of Pb of most analyzed herbs were high; most of them are higher than recommended values by the world health organization (WHO). Fortunately, the herbs that contain the highest Pb levels are the less commonly used medicinal herbs in Jordan. The mean Pb levels in the most commonly, commonly and less commonly used herbs in Jordan are 13.9, 13.1 and 16.9 μg Pb/g, respectively. The average dietary intake of Pb through a mixture of these medicinal herbs consumption, assuming 5.0 g herbs is consumed daily, is 79.5 μg Pb/day, which is higher than the maximum daily limit allowed by WHO. We conclude that most of the medicinal plants consumed in Jordan contain significant amount of Pb, and therefore, people of Jordan should not consume large amounts of these herbs.     

Temporal distribution patterns of metals in water,sediment, and components of the trophic structure in a tropical coastal lagoon of the Gulf of Mexico

Environmental Science and Pollution Research - Trophic transfer and bioaccumulation of trace metals have a profound impact on the structure and function of coastal areas; however, the metal...     

Valorization of quartz powder for drying shrinkage and carbonation resistance of alkali-activated slag cement

Environmental Science and Pollution Research - Alkali-activated slag (AAS) cement is one type of alkali-activated binders free from Portland cement. The main problems of this type of cement are its...