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131.
This study focused on using scale inhibitors for calcium sulfate that are not only highly effective, but also comply with
present restrictive environmental control legislations. In this respect, some biodegradable compounds-based biopolymers, such
as carboxymethyl starch (CMS), carboxymethyl cellulose (CMC), and chitosan (Ch), were evaluated at temperatures 90–95 and
130°C. The results obtained were compared with the performance of polyaspartic acid (PAA), which is well known in this application,
as well as other chelating synthetic polymers (polyacrylamide and amphoteric polyacrylamide). The role of the degree of substitution
(DS) of carboxymethylated biopolymer and the charge density of polyacrylamide (AmPAM-30 and AmPAM-50) on inhibition performance
of scale were also examined. The synergistic effect of PAA with investigated inhibitors was studied for economic and environmental
purposes. The results revealed that both the degree of substitution of carboxymethylated biopolymers and charge density of
polyacrylamide have a profound effect on improving the performance of the investigated scale inhibitors. The efficiency values
were correlated to the thermal degradation behavior (TGA) of biopolymers. PAA had the highest synergistic effect of all investigated
inhibitors, where the inhibition efficiency was found to range from 98% to 100%, at a temperature of 130°C, with low doses
of both PAA (2 ppm) together with biopolymers. This efficiency is observed using 20–40 ppm of PAA. The synergistic effect
of PAA (2 ppm) also showed enhancement of the performance of low doses of polyacrylamides (5 ppm) in maintaining soluble Ca2+ in solutions, increasing the efficiency from ∼57% to ∼100%, as well as its ecotoxicological property. 相似文献
132.
Zafar Fatmi Imran Naeem Abbasi Mubashir Ahmed Ambreen Kazi Fujio Kayama 《Environmental geochemistry and health》2013,35(3):341-346
Prior surveys conducted have found higher proportion of arsenic-contaminated wells in villages along river Indus in Pakistan. This study aims to determine the prevalence of arsenicosis skin lesions among population exposed to higher exposure in taluka Gambat district Khairpur in Sindh. The cross-sectional survey was conducted from August 2008 to January 2009 among 610 households. A total of 707 water sources (hand pumps/wells) were tested from the villages of union councils of Agra and Jado Wahan for arsenic levels with Quick rapid arsenic field test kits. A total of 110 households exposed to arsenic levels >50 ppb were identified. Case screening for arsenic skin lesions was performed for 610 individuals residing in these 110 high-risk households. Information regarding household and socio-demographic characteristics, height and weight measurements and arsenic exposure assessment were collected. Physical examinations by trained physicians were carried out to diagnose the arsenic skin lesions. After data cleaning, 534 individuals from all age groups were included in the final analysis which had complete exposure and outcome information. Overall prevalence of arsenicosis skin lesions was 13.5 % (72 cases). Of the 534 individuals, 490 (91.8 %) were exposed to arsenic levels of ≥100 ppb in drinking water (8.2 % to >50–99 ppb, 58.6 % to 100–299 ppb, 14.6 % to 300–399 ppb and 18 % to ≥400 ppb). Prevalence rate (per 100 population) of arsenicosis was highest at arsenic levels of 100–199 ppb (15.2 cases) followed by ≥400 ppb (13.5 cases) and 300–399 (12.8 cases). Prevalence rate was higher among females (15.2) compared to males (11.3). Our study reports arsenicosis burden due to exposure to higher arsenic levels in drinking water in Pakistan. Exposure to very high levels of arsenic in drinking water calls for urgent action along river Indus. Prevalence of skin lesions increases with increasing arsenic levels in drinking groundwater. Provision of arsenic-free drinking water is essential to avoid current and future burden of arsenicosis in Pakistan. 相似文献
133.
The Chambal river, subjected to industrial and sewage pollution, was studied with reference to the benthic fauna. Twenty seven taxa of benthic fauna of four main groups were observed at the stretch of the river: Oligochaeta, Diptera, Mollusca and Insecta (“others”). It was noted that the pollution input zone shows less fauna. The analysis of various physicochemical parameters showed an increase in pollution where domestic and industrial effluent were added. Changes in the benthic community have been explained with the help of the Diversity Index. The species diversity values showed a decrease from the prepollution point to the effluent discharge channel with an increase at the posteffluent point, indicating it to be a recovery zone. The coefficient of correlation was assessed between different physicochemical and different groups of benthic fauna. 相似文献
134.
钙基膨润土辅助对堆肥及土壤Cu、Zn形态转化和白菜吸收的影响 总被引:5,自引:2,他引:3
通过好氧堆肥和盆栽试验,探究不同比例(0%、2.5%、5%、7.5%和10%)钙基膨润土(CB)辅助猪粪堆肥过程及盆栽土壤中Cu、Zn形态的变化,并分析CB对白菜生物量及吸收Cu、Zn的影响.结果表明,在所有处理的堆肥过程中,可交换态Cu、Zn的分布比例逐渐下降,而可氧化态和残渣态逐渐升高,与0% CB相比,2.5%~10% CB可使堆肥结束时生物可利用态(可交换态和可还原态)Cu、Zn的分布比例分别降低19.84%~48.90%和4.94%~16.39%,并以10% CB的效果最为显著.进而开展的盆栽试验显示,施用堆肥后,土壤有机质和EC显著升高,而pH有所下降;CB辅助堆肥能够促使土壤EC的降低及pH的升高,稳定土壤有机质.与纯土处理相比,施用堆肥可显著提升白菜的生物量,且10% CB处理中的生物量最大(6.51 g·盆-1±0.34 g·盆-1).施用CB辅助堆肥后,种后土壤中生物可利用态Cu含量增加;但各处理中可交换态Zn含量分别降低38.91%、43.69%、46.02%、45.12%和54.65%.白菜在施用堆肥后Cu、Zn的吸收量显著降低,并且随着CB辅助比例的增加Zn的吸收量随之减少,而Cu的吸收量呈增加趋势.本研究表明,钙基膨润土能够降低堆肥过程中Cu、Zn活性,在堆肥施入土壤后仍对Zn有持续的固定作用,同时CB辅助堆肥可以提高白菜的生物量,减少重金属Zn在白菜中的累积,并以10% CB的效果最为显著. 相似文献
135.
Sharon Olivera K. Chaitra Krishna Venkatesh Handanahally Basavarajaiah Muralidhara Inamuddin Abdullah M. Asiri Mohd Imran Ahamed 《Environmental Chemistry Letters》2018,16(4):1233-1246
The presence of contaminants in potable water is a cause of worldwide concern. In particular, the presence of metals such as arsenic, lead, cadmium, mercury, chromium can affect human health. There is thus a need for advanced techniques of water decontamination. Adsorbents based on cerium dioxide (CeO2), also named ‘ceria,’ have been used to remove contaminants such as arsenic, fluoride, lead and cadmium. Ceria and composites display high surface area, controlled porosity and morphology, and abundance of functional groups. They have already found usage in many applications including optical, semiconductor and catalysis. Exploiting their attractive features for water treatment would unravel their potential. We review the potential of ceria and its composites for the removal of toxic metal ions from aqueous medium. The article discusses toxic contaminants in water and their impact on human health; the synthesis and adsorptive behavior of ceria-based materials including the role of morphology and surface area on the adsorption capacity, best fit adsorption isotherms, kinetic models, possible mechanisms, regeneration of adsorbents; and future perspectives of using metal oxides such as ceria. The focus of the report is the generation of cost-effective oxides of rare-earth metal, cerium, in their standalone and composite forms for contaminant removal. 相似文献
136.
Basit Abdul Amin Noor Ul Shah Syed Tanveer Ahmad Imran 《Environment, Development and Sustainability》2022,24(9):11424-11448
Environment, Development and Sustainability - Conservation of greenbelts is the most enduringly successful and popular basic need for today to protect green land, preserve ecological landscape and... 相似文献
137.
Mohd Imran Khan Iqbal Ahmad Abbas Ali Mahdi Mohd Javed Akhtar Najmul Islam Mohd Ashquin Thuppil Venkatesh 《Environmental science and pollution research international》2010,17(7):1347-1354